a little clarification
I am by no means an expert....but here it goes....
1. If you see a kit listed that has 1.) a single piston caliper or 2.) lists that it comes with spindles...it is likely a granada based kit...cal-mustang selles one of these. Usually will not work with stock wheels.
2. Stainless steel brakes kit is a direct bolt on application, and usually can use stock wheels. It is a 4 piston design.
3. Wilwood is a bolt on application, and is custom. You will need at least 15" wheels and is a 4 piston design, and I have heard it widens the track, therefore reducing the size tire you can run.
4. Baer I know the least about, but suspossed to be about the best...is a bolt on application and you need 15" wheels. They have a handy clearance template if I recall correctly. It is also a 4 piston design.
5. Other - I have seen some other kits out there that are bolt on that use various calipers and spindles, even some that use GM calipers...
6. Straight Granada - requires swap spindles, single piston design requires 15" wheels. Can cause some strange alignment and geometry issues with some aftermarket
suspension...global west, grab-a-trak, and the shelby drop, and negative wedge kits...
All in all the "easiest" is the SSBC.
There is the whole other argument of single piston vs. 4 piston calipers that let's just leave alone
I hope this helps...
This is all based on my days and days and days of research...again I am not an expert!
Ron