GROUND CONTROL: I have installed thier kits on many cars, usually there is major ride quality issues, -but with some cars this is not the case. I cannot say if there is a problem with the matrix/vibe application because I have not used them yet. We do have an advantage over other applications though, the shocks/struts have a very long travel, which smooths out the ride. I have my Matrix lowered about 3" with factory shocks and have not had a problem. I do know that the Progress Group has true coil-overs on the drawing board, as well as Tein.
http://www.tein.com/http://www.progressauto.com/ The last time I spoke with the Progress group they claimed that they would be making the coil-overs for TRD, I do not know when they will be out yet, I will try to findout on Monday and will let everyone know.