I did a search on Corral to find out more about X2C's control arms. Most guys seemed to be pleased but others were not.
For the price they look like they would be hard to beat. $149 for a set of uppers AND lowers, plus you get a lifetime warranty!! Obviously for that price I wouldn't expect them to compare to units from Griggs or Maximum Motorsports, but not everybody has to have (or can afford) the best. The general consensus was that they are great for street use/occasional strip, but if your car is a dedicated track car I'd probably look elsewhere (even though X2C does offer a more expensive version for the hardcore track guys).
I've heard a LOT of mixed opinions about X2C's quality of products though. Some have great experiences and some don't. Their shortblocks are much more inexpensive than ones from DSS, CHP, etc...and some people said they are great while other people say they are crap and "you get what you pay for."
The 1 product from X2C that I haven't really heard anything bad about is their Tremec TKO V1.0 tranny. That thing is supposedly bulletproof and their claim to fame.