good setup for p5xl - 9886/421021 for a smooth low end with crazy mid to upper rpm - 9853ss/41005 or 41021 for more bottom to mid and decent upper rpm ( little better mileage)- 9901ss/41021 or 41005 for the ultimate in mileage , odo100 , odo 77 or mc8 glow plug , restrictors are up to you really , i like the 7 or 8mm , usually the 7mm.

all tunings are really relative and depends on what you want out of the engine. p5 and plus4 engines are pretty tuneable as far as pipe , plug and clutch .