I'm recording the speedometer with a mounted camera then using a stopwatch to time the recorded run. I time it like 10 times then just average my times.
The reason I am asking is that those time, even the ones after the clutch change, seem too good. Way too good for our cars. 40-100 times in the 7's or low 8's would translate into solid 12 second quarter mile times.
Maybe your camera plays back at a faster speed than it records? Try real time with your stopwatch and compare. Or consider checking with a different stopwatch. I think you are being very honest. I just think there is something wrong with the accuracy of your measurements.
Just as food for thought, the web site of Road and Track has the acceleration curves for four seriously fast, quick cars all capable of running the quarter in 12.5-13.0 seconds:
http://www.roadandtrack.com/assets/download/0608_comp_chart.pdf
(chart is too large to post here)
The quickest of the four, the MB C63 AMG (12.5 second quarter) took 7.3 seconds to cover 40-100.
The BMW M3 Sedan took 8.3 seconds and covered the quarter in 13.0 seconds.
This would put your car in the high 12 second range! If you were almost a full second quicker than an M3 from 40-100 you'd be putting some serious hurt on him from a roll. I don't think that likely.
I'm also attaching the link to the acceleration curve for the new 370Z and a Porsche Cayman S, probably a more valid comparison.
http://www.roadandtrack.com/assets/download/0409_rt_caymanVS370z_chart.pdf
I think a properly driven MS3 with mild mods can take a stock 370Z, at least from a roll. The Cayman S, running 13.3 quarters takes 9.3 seconds for its 40-100 run, and would eat us alive unless we are very heavily modded and/or running drag slicks.
I follow this kind of stuff - not sure why. I guess I just want to know where we are in the automotive "pecking order." (Which cars I can pick on and which I should stay clear of - lol). But knowing these things made me think your measurements were off due to bad instrumentation or bad technique.
By comparison, my MS3 with mods in sig below, runs 40-100 in 9.5-9.7 seconds, depending on conditions, about dead even with the Z.
Your new clutch may be acting up, but I don't think those measurements you posted are accurate enough to help us find the the solution.