Technical info and opinion
If you buy the same specification ram and have a company microsolder them into your device, great! It should be fairly straightforward. Please take measurements of your device's performance, battery life, observations, and system info before and after updating and post back to let us all know how it goes.
Windows Mobile 5 seems to be built to automagically recognise the parameters of the Intel XScale CPU in it, meaning that switching the CPU to another of the same family should not cause problems. Replacing it would be an impressive feat to accomplish physically, so again get back to us all on this. You could get up to 800Mhz! Check out Intel's Xscale roadmap at http://download.intel.com/design/emb...s/30610501.pdf
Pocket Hack Master is a utility which allows users to overclock their HTC Universal; see http://forum.xda-developers.com/view...ight=overclock
My personal observation:
I'd be reluctant to try microsoldring surface-mount ram chips to my new Universal (has to be done professionally). My 64MB work fine, not to mention another two chips would potentially add 1.4watts (0.7watts each) of battery drain and heat power dissipation to my device. I've only got 1600mAh and tend to travel (no-recharge).
I urge other users to mod their devices in the pursuit of science and performance; both truely noble causes. Example, more ram would ease the running of Linux on this device. Please continue working towards a Linux port for Windows Mobile devices!