As a past owner of an '87 GTA w/ the 5.7 TPI,IMO,it's one of the coolest looking engines to stuff in a Z.Dan Juday popped in a 305 W/ the TPI and just looks sweet.So as far as appearance,way cool.Performance,well,the bone stock 5.7 was rated at around 225-245 hp way back in 87-89,plenty of tire erasing low end,but not a high revver.Either way,no matter what powerplant you choose,$$$=horsepower.There are plenty performance parts for these 5.7's,as well as for the LT,and LS,so I think it just boils down to personal preference.Good luck w/ the build,and keep the handful of us with the oldschool TPI's updated on your progress.