First, check to see that you are loosing traction on both wheels equally. Even if both are leaving black marks, if one is longer or darker than the other, then the traction-loc is bad. Easy, cheap rebuild. I couldn't hook, so I went all out, replaced the whole suspension except K-member and A-arms, and with Nitto DR 275/40R17 I still was spinning all over the place, I was pretty mad. Then I noticed that the right would spin first, then the left would catch up, then the left would hook, but the right was always longer and darker. Did a rebuild on the traction-loc with an extra clutch pack on each side and it made a huge difference. Not so much on the track as the street. It was funny making the WRX/STi/EVO and other AWD guys suddenly wonder where thier advantage went.
Trying to launch at the track with a 17" wheel is a oxymoron like no other. Even on drag radials. The sidewall flex placing the rubber down, that is the only way. I was hooking a 1.8 60ft on those DR's, launching from 1800rpm, never had the chance to use the rest of the setup. 15x8 welds now, we'll see.