Quick question

[slow vp]

I have two JBL GT122 subs i want to run in my commodore, what sort of amp will i need to power the two subs?

also does it matter if there in separate boxes?

thnx

[HCVP]

You will need a mono block amp. The amp you choose, will need to provide preferably (depending on your budget) equal, or greater power, to that of the reccomended input of the subs. I did a quick search of your model number, and it returned some 3 way floor standers intended for HT use. So i'm unable to make any reccomendations, until i have a budget, and some more infomation regarding your subs.

The impedance of the amp is also important, matching the impedance levels to that of your subs voice coils when wired in certian configuration.

As far the enclosure is concerned, you first have to decide whether you would like a ported, or sealed setup. There are no advantages, or dissadvantages to using seperate enclosures, or a single enclosure for both drivers, just personal preference as far as building them goes. The build and layout, and direction in which you face it will have the most impact.

[slow vp]

yea ill give you some info off the sub itself.

nominal power rating: 140 watts
Peak power rating: 280 watts
Sensitivity: 95 dB
impedance single - 4 ohm
frequency response: 25hz - 3khz
2" single voice coil

thats all it said on the subs themselves.

as for a budget i dunno really not really wanting to spend too much though.

[HCVP]

Ok, 2 subs, each single voice coil, of 4ohm.
When you have 2 or more of the same speaker/sub, you can wire the voice coils in different configurations to change the impedance. It can either be halved, or doubled.
So with your subs, you would want to wire them together in parrallel, to produce a 2 ohm load.

So for the amp, you will be after one that produces anywhere from 300 rms and/or higher, @ 2ohm.
Without a budget, it's hard to go reccomedning anything. But as far as cheap, and relaible amplifiers go, you might want to look at one of these> Ryda Car Audio - Clarion Car Audio APX1301 Car Amplifier($158.85)

This amp produces 400 rms @ 2ohm, so you have a little bit of headroom, and is fairly cheap. I have used these for a number of people during budget installs, and have yet to find anything to complain about.
I've also used a pair of these some time ago, in my own install powering 2 Type R 12's, and again, no complaints for the money.