For your average joe like me, pulling the engine and upgrading the turbos for me is NOT a DIY. $3k for a turbo kit is one thing, but when you need to double the cost for installation... point of diminishing returns. However if I had a Supra with the turbos sitting on top, I'd be much more willing to attempt upgrading them. I've heard of people putting on a single turbo in a day or two in their garage.