... k atm my car has a 4inch turbo intake side, where the filter goes.... it goes to 3 inch and then i have a k&n... i did this cuz it was wat I had at the time. I'm gunna order a 4inch online now and was wondering if it will effect my tune?

 

anything that changes air flow will affect a tune.

 

Unless you were running extremely lean I wouldn't worry about it at all.

 

My tune under boost was very very conservative and very rich...(not too rich but very nicely rich) under vacuum/cruise I had low 14s. so nothin was extremely lean.

thanks for ur guys input.