i saw a thread a while ago about a set of control arms people were having problems with but im not sure if it was mac. they were actually splitting the welds at the bushing and basically falling off. might be something to look into. not sure if they were mac or granatelli though
the granatellis are the ones that break. not sure about macs. for 100 bucks id get em. if they suck they suck your out only 100 bucks. i remember there was a huge thread on the granatellis breaking and JR.Granatellis response was to be a total douche about it.
Depends what you want your car to do.. if you want to build a corner carver, then you don't want the MACS - or any other control arm with hard poly bushings on both ends. You'd want something like Pro3i's or MM's pieces that have a 3piece bushing on one end that allows the rear suspension to move around without binding up real bad.
If your after straight line performance and don't care about bind, then they will work fine for you.
for a 100 bucks i would think its a deal...but like mavrick said the poly bushings will bind up in conering.....got to maximun motorsport web site and read about their control arms. i almost bought a set of macs, but after reading that i bought mm