It should be pretty straight forward. It's an in-line plug and play unit that won't need any wire splicing. Like jgos929 said, go to their web site.
www.powercommander.com As far as the money issue is concerned, I'll leave that for you to decide. Just one thought, however. Regardless of what you could get selling the PC, it won't be enough to replace it down the road. Just my two cents...