I didn't see mention of you having a cold air system. That is well worth the effort. How about collector extensions if you drop the exhaust? I would try 18 to 24 inch extensions. Those two items alone could beworth more than two tenths ET. Pump the front tire pressure up some, every little bit helps. Be sure you have an excellent air cleaner base for best air entry. If your heat riser passages aren't blocked, do so.