I installed my infinity 6x9 3 ways in the back yesterday and heres my conclusion: It really picks up the mid-bass lacking from the front and adds some rear fill but it also sounds a little off-stage. Before, i had the back 2 stock ones disconnected and it sounds a little better like that for the driver. I think it has to do with sound delay, but once i get my alpine cda-7894 with time corrections, itll be all good....