Does it matter what version of Gameshark 2 it is?
 

I'm gonna buy a GameShark 2, so i can use the cog swap method to boot up backups of my ps2 games, i was wondering if it mattered what version it was...

No - any version with the cog/swap method will end up knackering your PS2. If you get a modchip, v1.9 is reckoned to be best.

If you have a v4 PS2 you will need a gameshark2 v1.4 or better to load backups, As Charlie stated you should buy a modchip. It's to late once you have striped out your PS2.

I know, i am going to get a modchip, I'm gonna get the Messiah Playstation 2 upgrade, but i don't have ps2 yet, and i'm buying it soon, so i'm gonna use the cog swap trick when i first get it, then i'll order and install the modchip