I just picked up a set of SU Rams (mini velocity stacks) that I put under my K&N filters and so far I'm very pleased with the performance results.  I also switched out my smogger M58 needles to N27's which I'm sure added to a lot of the gain.  Shipping from the UK took about 2 weeks.

 

http://www.ebay.com/itm/151414457890?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

 

I think anything along this line of rolling that air into the mouth of the carbs rather than breaking it over the square corner is invaluable. I've run the Stub Stacks from APTFast for years and really like them. Of course that's on a 510 where distance is limited......