Autovista was a feature that I am jealous of in Forza 4.
These games are for car enthusiasts and petrol heads (among others) and being able to essentially going to a "car porn mode" and oggle at cars and mess about with doors and trucks and hoods and see components is something that we will naturally find interesting.
I don't play Forza but I can recognize good ideas when I see them. Turn 10 has some really great ideas and my personal guess is that it's a mix of passion and being the underdog as well as a western take on racing/driving games that steers them to included new and interesting modes.
PD seems to rest on their laurels more often then not. I love them for what they've done and I grew up with them, but sometimes I just shake my head at the excruciatingly slow pace the GT series evolves at. They should do what the Japanese have always done, take other people's ideas/inventions and make them bigger/smaller, i.e. improve them...shamelessly.
I would love for PD to rip off many ideas that Forza has, it would make GT as a series more complete, more interesting and in the end more fun.