My 97 Dinan SC E36 M3 with 135k is in trouble. Due to known issues in both the head and block, I am fairly certain I am shopping for a used long block. My budget is pretty tight, and this is my biggest DIY project ever. Any advice on where to aquire this pricey piece? Any of the salvage opperations with good reputations & results? Any advice in this matter would be greatly appreciated.