I prefer the straight fenderwell intake over a normal fenderwell and hot air intake (Open cone) I've run all 3 and have had much better luck and results with the 4" straight. Especially at the track. Yes i know its all in the butt dyno but it also just makes more sense taking the air from behind the headlight than from the engine bay or having to clean it often when its down in the fender.
As far as LS1 throttle bodies... who still makes the adapters? Also, don't you lose cruise control? Would the ported stock tb give me all the airflow i will ever need? I have a 98 where i removed the bar and used a 99 style maf.... or is a 99 better epoxied up or does it not make a difference?