I'll add my 2 cents, the ebrake light may be coming on when you're launching hard due to low brake fluid, if you launch hard, the fluid may travel to the other side of hte reseviour and the sensor may think you are lower than you actually are.
2. as hotshot said,
www.3sxperformance.com I think they may polyurathane ones.
3. I would agree it is time for new turbos as well. Just remember with any turbo upgrade you will need supporting mods too, and it sounds like you want to go big. If you don't take it to the track too often and just want a fast as hell street car, I would suggest 15Gs, they are the same housing, so they can be direct bolt on replacements but they are still damn big.
4. As hotshot said again, it's spark blowout, you probably still have platinums in there, replace with copper and gap .28 and you wont have any problems. Just realize copper plugs do need to be replaced a bit more often than platinum or iridinum.
Good luck