I used a Alpnie 9815 for the head unit, JL XR650CSi for the front speakers and JL XR650CXi for the rear. I don't listen to my music very loud so I went with the larger rear in hopes of getting enough low out of them so I don't have to add a sub. They seem to be doing ok but I could use a little more bass. I have to play with the head unit and see if there are some settings that will make me happy. The system as on the whole sounds very clean and overall I'm very pleased with it. If I get a wild hair up my ass I may still get the amp and sub. I'm looking at a 5 channel Soundstream Rubicon 550 amp to drive the whole sytem and their Rubicon 10" for the sub. That will have to wait though. I think I'll do a catch can and the PSI^3 S.E.C.S + external sensors next and some SS brake lines and fluid after that. By that time maybe a ECUTek will be available. Then I can do the downpipe and a custom tune. Oh don't forget wheels and tires for the track. Maybe a little seat time with an instructor. Probably be time for some more stree tires soon. Arrrrrrrg so many wants/needs and so little money.