LT1 throttle bodies

I've been considering an aftermarket throttle body. I just have a cold air intake w/ twin K&N's and a flowmaster catback. My stock throttle body has an air foil in it. I saw a trick flow and and it was about $60 more for a BBK more both were 58mm. I dont know much about these so if someone could help that would be great. I not expecting to gain a bunch of power i just wanna bolt on a few things to make it a little better. I dont really wanna lose any fuel mileage either.....so what do ya guys think

The bores in the stock intake manifold are only 52mm, so bolting a 58mm throttle body on the manifold, without opening up the bores to match would be pointless. Also not needed with a "stockish" engine. Would not affect fuel mileage, but the change in throttle opening can cause problems with the line pressure in the 4L60E automatic.