It should already have a synthetic blend in it, it asks for SAE 5W-20 premium synthetic blend.
nah, the drop-in is worth 5-6 hp, assuming everything else is in tune. With a good plastic CAI, you can pick up another 5-6, but you won't do any better than a total of 5-6 with a metal CAI.tex117 said:The drop in filter gives you the majority of the HP, probally 8-10. If you got a good cold air intake with it you have gotten and 4-5.