When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Do you mean their ZL435 or ZL465 kits? I piece mealed their 465 kit. The only SLP part I used was their 1.85 rockers. So with Kooks 1 3/4" long-tubes, Halltech cai, rockers, x-pipe with cats, Corsa Cat-back and tune, my car made 393rwhp/383rwtq SAE. That's basically the same parts in that kit and I assume using their parts would get you close to those numbers as well. I think they now include an u/d pulley as well.......maybe gears too for better acceleration. I later add a ported intake which brought me up to 397/387 at the wheels. I didn't want to open up the motor at the time but now looking back, I think I should have just gone with a cam. You will get more power even with a mild cam over the rockers.
I have the ZL435. I am very happy with it. I can definitely feel the difference SOP. I have recommended it and the people that have done it are very satisfied with the results.