It's more important to get an even compression across all 4 cylinders, but you should be getting about 180-190ish psi on each cylinder
As far as I'm concerned, a panel filter in a standard air box is as good as any aftermarket filter on the market
And it might be a good idea to fit a catch tank, doesn't have to be fancy, my old one used to be a 500ml bottle of water before I made it a catch tank lol, just make sure you put a slit in it so the air can escape
