I have an 07 Chevy extended cab (classic) wanting to replace my 10s with a 12 with more power the amp I have pushes 700 rms @ 1 ohm
Someone recommended the JL slim is that going to be my best bet?

Hell no

no.

What would be best bet then? It's going to have to fit under the bench seat in back box and all

your not going to fit a 12 under the bench of a truck unless you raise the seat. lmi sell rear seat lift kits but they are expensive.

if i were you go to a dedicated professional box builder. have a box made for 2 8 in subs. sundown sa 8's in a T line. they will slam harder than a million slim line 12's or 10's ever would .and will hold up against the popular 10's and 12's on the market for the price of an 8'' sub.

my buddy has a 2006 ford f150 with 3 of these little bad subs and they get down hard.

already has 2 10s and they did ok but they didnt hold up a single 12 will fit under the seat they make boxes for my truck but which one should i get lol

trust us. that box is
GARB AGE. its most likely sealed because a 12 would need much more room for a ported enclosure which you most likely dont have under the seat. those truck boxes are junk pre fab garbage tuned very high dont matter if you buy a million dollar top of the line sub it wont get low. if your still stuck on buying a pos box and trying to cram a 12 under the seat then go ahead. but your wasting your money. there are a a bunch of little 8 in subs that will out do a 12 n a proper enclosure. (PROPER ENCLOSURE). a crappy sub will sound good in a good box made for it.

2 10s will easily hold up to a single 12.. and have better quality. wtf are you comparing 10rms to 100000000rms there's a difference m8

Premo sounds like he knows what he is talking about. Box definitely makes a world of a difference. 2 8 sundown subs have hit 145 and i was there. Lol. Off of 1000 rms?

noway