If I were him, I'd declare the subject off limits for the next two years. He made his offer and if anyone continues to try to discuss it, the offer will be taken off the table. 

Apart from that, can you imagine the COST of insuring a new Merc for a novice driver! 

Goodness gracious.  If I had said that to my dad?  I would have been getting a shiny new huffy special from walmart to drive till I left the house.

I think he stands his ground.  That car is what he is offering.. it's a nicer car than most kids get if they get one at all.

If she wants something nicer.. she can save and then they can use that car as a trade in or sell to go towards what she buys... but he is not putting any more money in.... what is in that car is it.  Mom.. grandma.. they can provide different if they want different.

He said we shouldn't have even offered

Well, he offered, was shot down, so now he knows exactly where she stands and the onus is now on SD and BM to figure out the car thing. DH should not put up any money for any other car, new or "recently used". He let her know what he was willing to do and it was declined. The end.

He needs to shut down any and all attempts to manipulate him through guilt.

So, Dh is a mechanic that specialises in BMW and Minicoopers. Its common for these owners to have an older model and want to upgrade, so then he will offer them trade in value, which is FAR below retail. We are talking a few thousand dollars. And then he will fix it up, wash it detail it and resell for triple that.

But the average person doesnt have that opportunity and at best will find a used Mercedes for 5-10k. MAYBE.

SD14 is very spoiled and entitled. Best to stand your grounds and tell her its that or BM can buy it and insure it and pay for repairs...

Luckily we dont have that issue. Im just pushing for SD15 to get into driving school and get driving.

I'd take any and all cars off the table for her.  Consequences.

I can't even. 

No, my son got a car for 3K, a used hatchback. It is a great little car and completely reasonable for a teen to drive. SD needs to get a freaking grip. There is nothing that says you have to provide her a $1 towards a car or insurance. She really screwed up with her attitude!

I was given a car as teenager. I crashed it. I got more new cars and lost them too. My parents paid my insurance and gave me a credit card for gas stations. I was given everything. Not my parents fault. I'm responsible for my own life. I see my oldest sister and she is successful on so many levels. Her backyard looks like a tropical resort. She worked hard for everything she has. Parents never gave her a car or paid her insurance when she was a teenager. She had to make her own money to get what she wanted.  

You and your husband are doing the right thing. Getting SD the car she wants won't help her it will only hurt her.

Skids are not entitled to cars, hell, kids in general aren't entitled to cars, let alone a new Mercedes. A 2016 is hardly a "used" car. She's lucky she isn't getting a 2000 rusted out Ford Focus with 300k miles on it with that attitude. And BM demanding that DH buys what she wants is ridiculous. 

I would tell SD that the offer is off the table due to her sense of entitlement. She wants a car, she can work for it. If she won't, then BM can step up and buy it. Nowhere in any CO does it state that parents must buy cars. 

I would never mention the word "car" in her presence again.

WTF? Why on Earth does BM think DH is going to buy the 16-year-old a $40K car? LOL.  That's insane. 

My first car cost $100, had rust spots that looked like bullet holes, and I had to climb in through the window, because the doors didn't reliably open.  Oh, and I was 20, not 16.

What a spoiled brat.  I wouldn't contribute anything to her, period. 

Id buy her a toy mercedes key chain for her 16th with a card "Here ya go pumpkin. Use it in good health"

Your BM is what is wrong with this world. They raise entitled selfish POS kids and the rest of the world has to deal with them.

Your DH should stand his ground and NEVER utter the word car in her presence again. SMH

Why would you even offer your car for her? I don't understand. She's an entitled little brat, so why offer anything? Let BM and her parents feed thst monster.

It's really important to begin managing kids' expecations about life's larger responsibilities (cars, college, housing) at a young age, realizing this is far more complicated when there are two sets of parents invovled.  My two SS's were told by their mother and stepdad that they could have any car they wanted in their early teen years.  DH (mistakenly) assumed that since he had grown up with nothing, always bought his own cars, and still didn't have a ton of $$, that they would somehow magically understand that cars were up to them.  Stepdaddy bought oldest SS a new pickup.  Then BM divorced him, and they both declared bankruptcy. StepD asked us if we would take over the payments on the truck... we said no thank you, and bought SS a "vintage" (LOL) BMW for a couple $K. SS#2 and DH went to the city to look for a car with a budget of around $10k.  They came home with a $25k BMW.  I made every payment on the damn thing, and DH paid for insurance and gas, until SS burned up the engien b/c he ignored oil light when it came on.  (He was on his way to Vegas to "invest" the Pell Grant $$ he had fruadulently claimed, but that's a whole 'nother story.)  Fast forward 14 years and my kids are ready for cars.  We learned a couple things:

First, you gotta stay on top of expectations and be crystal clear on your intentions and how much you can afford to help, if at all.

 Second, although cars may be an extravagent gift for a kid, if you can afford a safe, reliable one for them, it's a gift that gives back to parents in convenience and peace of mind.  

Third, it's important a kid contirbute something.  My kids each contributed $2k they earned working summer jobs. Our "deal" is that we pay insurance.  We also buy gas during the school year as long as gpa 3.0 or above, and they are involved in year-round extra-curriculars AND community service.  As we can afford it, I want them to focus on the more important stuff.  If we couldn't afford it, would be different.  I make sure they know that.  Kids buy their own gas and pay for one oil change over the summer.  

It's really hard when you have a Birth parent making promises and statements about what "loving parents" should do for their kids, and then inflating the resources of the other parent. My SS's are in their 30's, and we are still buying them cars, paying off their cars, paying to get their cars repaired, and getting s[p]it on when we tell them that $800 set of new tires is a "birthday present". (He was thinking  a new laptop and a dirt bike, LOL....).  Meanwhile, 17 year old is trying to save money so that he can "trade up" to a better car when he goes to college in 2 years.  He's under zero assumption we would do that for him. 

Do not give this little shite so much as a bicycle until she changes her attitude. Make her volunteer at a school for underprivileged kids (or regular kids if she's that insulated from real life) or find some other way for her to realize how ridiculous it is for her to turn her nose up at your car and demand a fricking Mercedes! Maybe if she shows sincere appreciation, consider putting your car back on the table. If you want, anyway. And BM just needs to be told to stfu. 

LOLLLL a brand new Mercedes!!! Have BM call around for insurance rates on that too!! SO gave SS17 and SS18 $2500 each for cars anything outside they had to save. They pay their own insurance too. 

Something else to consider re: any vehicle you may purchase:

Put a dash cam in it and tell SD it is to be ON whenever she drives. If it's not on and you all find out, the car goes bye bye.

If it's legal in your state (and it might be - check to see if this helps insurance, too), have a cab cam, too, to monitor who is driving and how they're doing. If BM is driving, or SD behaves recklessly, the car goes bye-bye.

DH and I made it ABUNDANTLY clear to OSS that ET is never to drive the car we loan out to him. Until he graduates college and we sign the car over to him, it's OUR car in OUR names on OUR insurance. He can drive ET places, but he drives it - not her. She has wrecked too many vehicles to be trusted (and if she wants a better car, she can go buy one).