Basically... throwing a lot of money into an inexpensive guitar just exposes all the flaws that make it an inexpensive gutiar. Putting high end pickups in a guitar with a particle board body will just sound like the best sound particle board around... it won't hold a candle to an ash, alder, mahogany... etc. bodied guitar.

Basically it's not worth dumping money into.

Granted... it can be worth putting some money into an inexpensive guitar. Putting decent pickups in one and updating the electronics... maybe a few cosmetic touches like a pickguard or something and viola... you've got a decent axe without spending a TON of money. I would rather save for a nicer guitar than pour money into a lesser value guitar... it just makes more sense in the long run