You need to mess with REX for a lot of time, so that you get to reveal the beast inside her
Start with some guides on various internet sites (overclock.net, overclockers.co.uk off the top of my mind), and the most important for SPi 32M ... Play with various BIOSes

Forget all about P5E3, and mostly focus on REX for fast SPi 32M runs My gosh, I've told you before but can't resist, your ram kit is superb !