Best places to buy chips and HDD troubles

[Cyber Akuma]

Im not in love with it, I just cannot at the moment afford a new one, especially not a premod.

Are there any guides about reinstalling/tweaking/etc the ps2 v4 lazer if it started screwing up on me? Because I dont have much of a choice, I might be able to make the money to buy a premod v9-10 in two or three years, and mostlikely will if by then my ps2 is starting to screw up, but I cant afford it now. So ill mod my V4... but.... im looking for a mod that will work with the v4, boot anything (especially original imports, thats the main reason im getting it) and will with the the hdd and actionreplay/codebreaker.

The only modchips I know that do all these (or claim that the firmware upgrades will soon) are the dms3 and the matrix infinity, which is why I want to get one of those.

Edit: I was reading through many identification guides, and all of them said that my ps2 can actually be either a V4 or a V7, is there any way to make sure which it is?