well the reason for that being...
i only have so much room/money to work with.. i figure if i buy a 15.. i can either run it ported for now.. and if i ever wanted *more* i could buy another 15 and run em sealed... (def wont have enough rom for 2 15's ported) i can run 2 12's ported (usually) but i wont have enough money anytime soon to buy two good twelves and one really solid amp or two decent ones... cause then the eletricial stuff comes into play ect... and i only got a stock 85 amp alt ...
but ia ctually looked at the manuals of both the power series and older GTO and their almost identical in frequency response.. the gto just seems less sensative... and i havent heard good things about gto subs... so now im starting to cross the power series off my list.. cause if it sounds like shit i dont care how loud it is =P
i just wanna find something that will sound good.. hit hard... and i wont regret buying 6 months from now..