you'll only lose about 8hp over your sweetspot powerband. but. 8hp is 8hp is 8hp... get an itr manifold, call it a day.. btw... I make custom rail fittings for those manifolds so you can use the stock rail with your stock fuel line. I also make fuel lines for those that need to extend them. (i.e. CD5 with ATR mani, fuel filter down and on the drivers side, stock line not long enough).