Which turbo should I put on my Mustang?
Either one sounds like a winner to me. The only turbos I know anything about are on tractors and semis. Truthfully though, if you want it for a street car, you really don't need any more power than that. I'm sure that the manufacturers have web sites and tech lines so use them. Tell them what you have and what you want it to do and they can point you in the right direction.
I always liked the Fox body 'stangs. They are easy to build on and always respond well to modifications. They are good looking cars too.
Good luck with it, and have fun.