rear discs need help.

[292farmer]

i recently heard a scrapping from my rear and pulled wheels off to inspect brakes and well...its bad i need everything and to give u an idea their 12in brakes worn to 12 and 7/16 and so thin and see through u can twist the drums with your hands(im not kidding). anyways priced everything out and came up with 375-425$(including lines) so was thinking why don't i use this as a chance to but rear disc brakes and think i found a good kit that costs a little more then my stock parts, heres the linkhttp://www.blackbirdscustomtrucks.com/index7.html#4d60 has anyone dealt with these guys is that an reasonable price? are their other kits avaiable? i couldnt find any. BTW my truck is a 72 c25 gmc with a dana 60 im looking at kit w e brake. thanks everyone.