They are serious about their stuff and you get what you need! Brackets and sometimes cables... Your still saving more money than going to a shop to fab up brackets and install...
They have GREAT tech support as well, if you get stumped...
i bought my alternator off ebay for 65$, Chrome GM one wire, 105 amps. To install it i just flipped it upside down and it bolted right up no problem, no grinding or anything.