Well i would recommend getting a 3 way upgrade set like i did cuz then u get 3 way cross overs and u can hook up ur componets on that as well as for hz on teh 6 1/2s i would say they prolly will play up to around 5K hz thats for a quality driver though, like diamond or mb quart, and honestly I think 6 1/2s would be better because the 10" subs are not going to play as low as my 15 does and i have plenty of mid bass w/ my 15 and 6 1/2s
