I am going to order a Yosh Comp. Series full exhaust and K&n. My next question is will 150/155 jetting be alrigth with two 1 3/4" holes cut in lid. Or is it worth taking lid completely off and running different jets, if so which size?

 

What are you putting this on, and what elevation are you riding at?

 

2002 Raptor - I live in Michigan don't know elevation.

 

You should be fine with the 2 holes & 150-155 mains. If you take the lid off, you'll gain some more top end but will need to jet up to 160-165 mains. The downside to no lid = water in airbox = wet filter = rich jetting = sputter = "I guesss I should have left the lid on."
If you run in sand or dry areas, take the lid off, jet up, & enjoy the power!