I would just go with what ever you like the best. I agree that there won't be a noticable difference between them. I personally am going to get the injen straight tip. I have an injen CAI but all it does it get really dirty really fast. As far as looks goes, I like the K&N Typhoon. If you are interested in anything just PM me.

 

th stillen is heavier, but in the back, if you run a stillen header, crawford cat, and stillen cat back, you actually lighten the car and the stillen puts out the most power of all!

 

My point is:
1st, Stillen does not made more hp than others, because there are so many exhaust are tested yet, especially most of the high end one have not been tested (eg, Greddy Ti, Apex't PS,....etc.)

2nd, If I remeber correctly, sport Z magazine didn't test Greddy and other Japanese high end exhaust (Apex'i PS, HKS Ti...etc). So that still doesn't proved Stillen has most of gain compare to all exhaust.

3. Stillen weights around 10-20 lbs more than stock, this might not show big difference compare to stock, but some aftemarket exhaust weight 20 lb less than the stock. Which mean, these lighter exhaust actually weight 30-40 lb less than Sillen. Now 30-40 lbs is not a small difference. and if stillen only gain 0.5 hp power more than these lighter exhaust, I consider overall perfomance, stillen is no that good.