So I've gathered the C5 13" brake components. I've got Belltech 2" drop spindles. But when I tried to put them together it's no go! For some reason I thought they were made for bigger brakes but they're made for the stock brakes to fit. Now I have to chop the Belltech spindles! I have spare stock spindles but no spare Belltechs if I screw it up. Fingers crossed.

 

Also keep in mind that drop spindles will not allow you to run wide wheels up front, so if that is also on your list of must haves, sell them...

 

There are good arguments for both 245 w/drops or 275 w/ext BJ. Educate yourself and make an informed decision (read 'The Grip' and part 2). For street driver practicality, I don't think wider than 275 will be comfortable, but there's always someone who says their 415's are comfortable.
Drop spindles are hard to find, so the 275 w/ext BJ is by far the more available option, today. As long as you make an informed decision, go have fun!
Post pics of the spindles, maybe we can help w/mods. I have Racecraft drop spindles with 13 x 1.1 rotors and FSL(narrow) 6pots. You can bravely go where some have gone before.

 

I've got 17 x 8.5 now and they look like they should be OK. I think the 2" drop plus other stuff I plan will more than make up for not being able to run wider. If I have time I may see if I can try some 18 or 19 wheels to see if anything would work with acceptable back spacing.

 

Yes I've been reading and reading and gathering parts for the big Winter project. Hope it's finally this Winter. I've got the spindles and will post pics of the set up. I also hope the 2" drop makes up for how HEAVY the spindles are.

 

Yes, I'm looking into 8.5" when I go 17". I think they'll fit, too. That would allow a 255f x 275r split, which would be acceptable to me.
Here's my stock wheel with the BBK pushing out .3" from stock.

 

I actually have 275s on the 8.5 rims and they seem to be ok.