i used to own a srx500
the stock bridge looks quite solid and zhnged already...
it's either the stock pickups or preamp that is extremely hot. you might be able to swap them for MM style pickups. not to sure. but you can ask cherns, he should know
other than bridge and pickups, IMO you owe it to yourself to change the nut to a TUSQ. you can pay a visit to zen to see which one will do. better still, find out when KC will be there. it is such a simple upgrade that you'll be wondering why you didnt do it sooner.
maybe install a hipshot bass xtender? couldn't hurt