I currently run a BBSC kit right now and you need to get a more detailed breakdown of all the pieces you are getting to compare the two. At first glance the first one at $5k seems to be throwing in a few more items then the second one. But there are so many factors.
A BBSC Kit Includes:
- All parts from original kit
- Paxton Novi 1000 or 2000 Blower
- BASCH Drive Unit
- Billet Pulleys, Brackets, Clamps, Intake Elbows, etc.
- Typically various sizes of boost pulleys to get 3/6/9/12 psi
- All hoses, fittings, nuts and bolts
- Billet Coolant Tank with Coolant Cap (do you have the drilling template for the firewall?)
- Fuse Box Relocation Bracket
- Blow off valve
- Illustrated Color Installation Manual
- Comptech Steel 6 Groove Balanced Dampening Pulley (superior to the Billet crank pulley that came with kit) or get a custom dampened one made
- Aftercooler/Intercooler
- Catch Can
- Blow off valve, if so what kind
- Cone air filter and pipe
Extras Included (not part of original kit, but very useful):
- Spare spider gears
- Spare set of bearings
- Pre-cut Factory Fuel Rail Cover (keep the original uncut for return to stock)
- Drilled, Tapped Oil Pan with correct AN Fitting for Oil Return Line (so you can keep original stock)
- Fuel pump (minimum Walbro 255 but size according to goals along with injectors?)
- Engine management (standalone or FIC)
- Injectors
Good luck, feel free to shoot me a message if you have questions.