i was thinking on upgradingthestock plenum on my 98gt for the 75mm trickflow and i was wondering if any75mm throttle body would be good ?
would intake and throttle spacers give a couple of extra ponies ?

 

all aftermarket TB/plenums will perform the same, give or take 1HP.

 

spacers are a waste. They "spin" the air, for no reason. This only applies to carburated applications where the fuel and air meet at the carb, in which a spacer would "spin" the air and get better fuel atomization. On out cars, the injectors are a long way down the runners, any "spin" would be lost by the time it made it to the injector to beter atomize fuel. DONT THINK ABOUT IT!!

 

GhostRider is right about the "spin", do not eveny think about getting a TB spacer that spins the air.
A Plenum spacer may help, but your money is better spent on other upgrades.