The forth gen booster firewall mounts are different. The one to go with are the 2002-2008 corvette units. You may have to redrill the pedal or run a 1/4" spacer between the bracket and booster.
Or you can run the tuff stuff booster part number 2229NC
http://m.summitracing.com/parts/tff-2229nc
Works perfectly with the DSE reduced angle bracket
http://m.summitracing.com/parts/dsr-050302
You will also need the pedal clevis kit
http://m.summitracing.com/parts/sum-760125