www.hifisoundconnection.com they are failry good I ordered my friend a 15" kicker L7 refurb and it cost $320, pretty good deal. I also ordered a Stinger 0 gauge amp kit for my self $112..(all prices are Canadian)
Hifonic amps are cheap for the output that you get...you can get one for around $300 bucks and you'll get around 1500rms for that.
I used to have 2 12" alpine Type R's they are nice subs...what size subs are you looking for?
That site; however, does not sell Hifonics amps, I'd try Ebay for that...my friend will be using one to run his 15" Kicker.
And since you want SPL, try Kicker subs L7(just spl not too much sq), or Alipne Type R's (nice mix of spl and Sq) alota people on here will also reccomend the Re SX subs also...but I havn't heard them.
Oh yeah when I used to run Alpine Type R's, they were awesome and I ran them off a CHEAP Sony Xplod amp, tossed them in a Future shop box in the back of my 89' Escort and I hit 139.6 db's and they have nice SQ as well...only reason I dont use them anymore (sold them)is I now have a sponsor and the amp I will be running would have killed my subs.