i was told that grooves in the pipe actually prohibit the flow of air and a smooth sided pipe is much better, even with bends. also, if air is anything like water (and im pretty sure it is) then 2 45* bends are better than 1 90*, it makes for smoother flow. with water, just one adjustment like that can increase flow rate by 5-10% easy, if you have 2 or 3 90's being used, it will increase it up to i think 10-15% (exponential i guess, can only increase so much).
and gabe, yeah TV FTW, he had that DIY posted back in 03 if not earlier and almost all G1's already have this type of intake.
as for the auction, so basically he guys a $10 filter and $3.50 pipe and pays probably $10 for the shipping. he is making ~$25/intake
looking through his feedback, he isnt selling too many of these, even though hes marketing them to other cars too:
Chevy 1500/2500/3500 but these people have already said that it doesnt work.