Best prices I have seen for the TT kit for a mustang...or any car for that matter.
I don't know much about them, but they responded to all the questions I had quickly, so I would check them out.
Http://www.itsturbo.net
Stage I is $2895 and has two T3 turbos...
Stage II $3495
This kit is design for those who want a little more than average. It includes everthing from stage I but upgrades the turbos to T3/T4 Hybrids and adds a Turbo Smart Type II vee port Blow off valve. There is also a second stage in car boost controller.
At only 10psi this setup will produce over 500WHP depending on other modifications and is capable of up to 700WHP.
Thanks,
DoranW