I know it has been some time since this post, but have you found anything that has taken that clunk away? I just got a 2006 roadster last fall with only 26k on it. I have changed all the fluids and spark plugs and it drives really nice, however still has that clunk in 1st and 2nd gear only. I changed the rear differential with Redline 75w-85, and I changed the manual tranny fluid and put in 1qt of 5w-20 oil and .9 qt of Lucas synth oil stabilizer. It shifts so much smoother and sounds clean, however when cold still hits that clunk sound going from 1st to 2nd. I'm thinking that I need to re-grease the drive shaft next? Anyone have anything that fixed this yet? Thank you.