Important context: the tone of the OP isn’t one of gloating. Your displeasure with his choice to post solely based on the cost of the vehicle is ridiculous and petty.
The ridiculous and petty posts are more from the people going after the people who "critiqued" the price.
Someone said, "That's a chunk of change," and the OP says it sure is, everything costs a lot now, and no way were the wife and I going to buy the other vehicle that cost even more. I don't think the person meant anything rude by it and was just making a quick comment on the ever-increasing price of vehicles. And OP didn't go off about the comment and instead handled it like a pro -- OP's friendliness diffused what could have turned the thread ugly even if the person had bad intentions with the comment, (which I don't think the person did).
Someone else said, "That's more than my mortgage!" That made me laugh. That just seemed a funny way to say, "Man, vehicle prices are out of control."
Other than one post I think went over the line, I'd say the price critique posts were either amusing or no big deal.
The posts that really turned this thread nasty are the ones going overboard about minor price comments. There's even posts of "hey why are you noticing the price?" even though this is a discussion forum and OP said the price in the first post.
I don't think OP is gloating. Showing off, or whatever nicer-sounding word someone might use, maybe. What else would someone call it. And that's fine. It's fun, and isn't pompous like someone doing a humble-brag. My complaint about the OP is not having a good picture ready. If you post about your new vehicle, you have to post a good picture of it. It's a rule.