I took the plunge and bought the tti early a headers to replace the Doug's I had on the car. The tti fitment is not as good as the Doug's. Even though my crank centerline was the 4-3/4" required by the instructions, I still had to shim the pass. side motor mount 1/4" to clear the idler arm. So far I am having to modify my shifter cable, brake lines, rear trans cooler line and the tti x-pipe exhaust adapters. Even though I have the complete tti x-pipe exhaust system, it will not bolt up without much modification and colorful langauge. The tti headers are beautiful and should work great, but they are more difficult to install than the Doug's.