Using the built in editor I got fuel trims within 0 to 1%. When I put it back to MAF/VVE it runs like crap. unexplained surge while cruising. Bucking/surging on take off. I gave up on VVE. My ZL1 runs smooth as stock when running MAF only. I think the HPTuners VVE editor should be looked at by the powers that be, and improved upon if possible. My 2 cents.