I currently have the intel x25-m mainstream 80gb as my boot drive and I'm running out of space and I'm looking to get a second one to raid 0, but I can't find the exactly same one on neweeg.com . my question is, if I get any intel 80 gb ssd would I be able to pair it with the one I have and make it a bigger drive?
Setting up a RAID can be done with different size HDDs (and, I believe different SSDs as well). The problem is that you will have to strip down and rebuild your boot disk to set it up in RAID.
The bigger question is why you want to RAID SSDs. Because of their properties the performance gains of RAIDing SSDs is minimal compared to HDDs. HDD RAIDs benefit from the fact that you have two simultaneous spinning devices which render almost a 100% increase in read/write from RAID. SSDs do not give a great performance boost from RAID.
The other consideration is that SSDs are notorious for disk failure. If you do a RAID O you will be doubling the chance of your system failure.
I recommend that you consider either an additional or larger SSD as an alternative.
You can raid two SSD's if they are the same size and generation (both sata 2) and you have to format or secure erase the drive you have and start with two clean drives. You will get a performance increase even though they are SSD's because that is what raid does. Setting up and using raid is risky because you can have a higher chance of failure which in the case of a raid the failure is one of the drives dropping out and then you have no OS. With a raid you want to be backing up your data daily so that if something does happen and you have to reinstall the OS onto one drive at least you will have a backup to restore your files. That backup will have to be on a seperate drive.