Well from all the plots and info i have seen an SMSP or Toda header makes as much power. Exhaust wise just about anything can make power SMSP makes an exhaust, Type 1 Racing just came out with a 63mm inner diameter setup. Headers will be the place power varies and so far Hytech just costs more than the other top power makes.

If I were to buy something other than a JDM 4-1 I would buy a Toda or SMSP depending on the cost.