Some do it for cost savings, parts availability and performance improvements. Everyone has there own reasons for doing it or not, but Dana Corp makes parts for all of the big three. I draw the line at engines, rear ends and anything visible with the hood open. Others go farther, and that's fine. Some drag folks have been running 2 speed powerglides in their Mopars and have been for decades with little grief over it being a "GM" part.; Some folks still look for 40 year old heater hoses to put on their cars to make them look like they were never touched from the factory on day one. It's all BS! I hated the way my cars ran, handled and drove in stock form. To each his own, but I do hate seeing Chevy motors in anything, but a chevy. I do have a lot of respect for their performance though, Ford too!Most people now days, with the exception of some people on this board and a few others boards would never know the difference anyway.Some Mopars are amongst some of the best looking cars ever made, and look what some folks have doe to ruin that with paint jobs, ugly oversized rims and the list goes on.