http://honda-tech.com/zerothread?id=527075

this the SMSP prototype for the H22. i believe it does make about ~20hp. i'm sure a larger collector will make power on the f22, especially a vtec model i would guess about 10-15hp. the problem is accord owners that stick with the f22 aren't generally the type to spend that much on a header. the ones that want power generally go h22, turbo, or sell it for something faster.

honestly if you know how to weld or know someone who can make custom turbo manifiolds they can customize a DC or Greddy header with a larger collector. also keep in mind a large cat will be needed. afterall the reason the collector is so small is to bolt to the stock cat.