Awesome times! I guess you have a manual (r154)? About how many Kg's is the car now? I await eagerly to see how you go with the twin pipes and higher boost.
I've not really done a quarter on a flat non-slippery road, but at 0.9bar the JZA does 0-100 in 5.66 with the auto trans spooled up (Apexi RSM).