I'm with most other folks. Nothing really to upgrade. Unless something is actually worn out, nothing will get better and it would just sound different with different PUPS.
Get some fret shields, polish the frets. I prefer to oil or wax the finger board. Get some chrome polish and do the Keys, Bridge and control plate. Put some fresh strings on it and play it for a while. If it floats your boat, then dump more coin in it. Personally, I like the older style heart shaped heavy tuners from schaller and the Kickazz bridge mentioned earlier. Brass nut too.
Get some fret shields, polish the frets. I prefer to oil or wax the finger board. Get some chrome polish and do the Keys, Bridge and control plate. Put some fresh strings on it and play it for a while. If it floats your boat, then dump more coin in it. Personally, I like the older style heart shaped heavy tuners from schaller and the Kickazz bridge mentioned earlier. Brass nut too.