I have discovered after purchsing a few torx bits that the correct bit for the rear caliper on the 1999 svt is a Torx Plus T45. I got the info from the BRAKE PAD REPLACEMENT under the HOW TO section under MODIFICATIONS, that i needed a torx t47 but that definetly did not fit.

1999 SVT removed res FMS 9mm metal impellar Koni struts PG Xenon 6.5 MSDS Y-pipe