I am wondering how easy, if I bought a laptop with the i5-430M, how easy would it be to install the i5-520 or 540 processor instead?. I think it may be cheaper to sell the 430M and just pay the difference between the two (as I'm looking, all laptops with 520M have a large premium compared to lower CPU). So, how easy?
Take a look at the sticky thread at the top in regard to how to take apart a laptop, as that will give you an idea of what you'll have to do. Remember, the slot for the chips is the same, but the 520 or 540 may require more power and a bigger/better heat sink, which may or may not fit. Your best bet is to pay the premium and get what you want to save the headache, plus you won't have to void the warranty.