Seriously, there'* not ALOT of difference between intakes. The trick to getting as much air in there is the pipe diameter, but also the length. Short intakes don't develop the velocity you need. In order to get an accurate MAF reading for the PCM to correctly respond to, you want a 3" pipe, with the smoothest bend possible, reaching all the way to the headlight. Slap a good cone intake on it at that point, and shield it from heat as well as you can.
Hector (from ADTR) bench-flowed and Dyno'd several styles before settling on this design. He found the 3" pipe actually worked more efficiently than the 3.5", and I believe it'* because it forces the incoming air to be more laminar, which is what the MAF needs.
Intake needs vary slightly when comparing the NA to the SC. The NA require laminar flow not only for correct MAF readings, but also for better flow through the upper intake runners. Turbulence is bad. The SC cars obviously 'chop it up' with the rotors, but the laminar flow is still necessary to develop the velocity to increase flow to meet the demands of the SC, AND to get an accurate reading.
All in all, 3" is best for MOST cars here. A heavily modded SSEi might be able to move up to a 3.5", but I think porting and polishing the TB and SC inlet would be necessary to take full advantage of that.
There'* info in Techinfo on some of this, but I'm assuming you've already read it.