I have a 4 door Gsr and I had recently redone the head. I was having problems passing emission. I tried every trick in the book to pass and didnt. I found out that I had bent exhaust valves. I figured if i was gonna replace, why not upgrade a tad bit. I had all exhaust valves replaced, the head dipped, port and polished along with the exhaust manifold. New gaskets, belts, water pump, you know the deal when you take it apart. Anyways, I finnally pass emissions after I replaced all of these things but I had to retard the timming for it to pass. I had someone set the timming back but im not sure if they did it right. Let me tell you what I am experencing and i could use some good feedback please. First, I drove it around a little and noticed that I dont have a lot of get up in 2nd gear and a little in 3rd as i used to. In 1st i shift at 3000 to 3500 rpm and then in 2nd around 2000 to 3000 its a little sluggish and dont get up as fast till after 3000 and i shift at 3500. Same goes with 3rd but not as bad as 2nd. Then i started to notice a little smoke come out from my hood, then that went away. Someone told me i need to let the head settle and the valves also set in place cause they are brand new. They say after 1500 miles it should and then get the timming bumped up. Im not sure but is he correct?