JBL is ok, but the bad thing about the gti subs is if you blow it you cant recone it, you have to get a totally new sub. Its in the design of the flat coil i believe. They have that patented as well for some reason, weird sub. Personally id look into other alternatives, xxx 15, brahama 15, stereo integrity d2 15 just to name a few. Id recommend re sx 15s as well