I get bored pretty quickly and easily if the conversation revolves around specifications and prices of everyone's luxury vehicle, number of square feet and level of extravagance in their latest housing purchase, or how expensive (but how awesome!!) their last week long all-inclusive resort vacation was (and how many free beers they chugged down at the bar). I can usually manage to either steer the conversation away from this idle banter or I can usually manage to walk away or find something interesting to stare at with my back towards them. That makes me an ******* I guess.
When I think about memorable conversations and having a good time with family, friends or colleagues, discussing how awesome (and expensive!) their latest transport device acquisition was doesn't rank very highly. I would be the guy to say "wait you just paid $20,000 more for that model of car versus the non-luxury version, and all it has is a couple extra gadgets that will be technologically obsolete in 3 years, a 20% larger engine, it can accelerate 12% faster, yet gets 15% worse gas mileage?"
Reflecting on memorable conversations I have had with family, friends or colleagues, it is usually something significant we are discussing. Their goals, dreams, aspirations, plans for the future, something unique they did or are trying to do, or some interesting topic like history, art, science, technology, religion, philosophy, or politics. I recall a cocktail party where I met a friend of a friend. This guy and his wife were both high school teachers, oddly enough at the school a few blocks from where I grew up and where my parents still live. The guy was a history teacher. We had some polite conversations about the host's wine selection, then the classic "so what do you do?" line came out of one of our mouths. We ended up talking for another 30 minutes or so about some fine point of history I had been reading about recently. It was one of those curiously rewarding conversations with a relative stranger that was very satisfying at the "Great Mind" level. If we had discussed his make and model of car and how awesome his new granite countertops were, it would have been a 3 minute conversation quickly terminated by a "well it was nice to meet you"!
To bring this back around to the OP's question, I think it is ok to talk about your new stuff that you are proud of. You know your friends and they know you. They are probably just looking to get affirmation that they are successful. Congratulate them on how nice their new shiny thing looks and then move on to other topics. If talking about your new bling is all the relationship is built on, then it seems like a fairly shallow relationship.