3G w/ 3.0 has gotten SLOW. What should I do?

[pixelator]

My ages-old baseband 3G running 3.0 possibly needs a total fresh install. It takes sometimes 20+ seconds to load text messaging and everything is lagged to *&^%@!

How do I:

1). Rejailbreak (if needed) with 3.1 and KEEP tethering, pref. as reliably as I was doing with the 3.0 easy hack? If PDANet is the only way, so be it, it's just that I've paid for that app several times in the past for PPC and Palm phones - I'd just as soon not have to do it again.

2). Clear out all the junk causing the phone to be so ungodly slow but later restore all my contacts, apps, etc. including Cydia stuff?

Thanks!

[time3993]

Have you tried this: Making the iphone 3g 3.0 faster

Some people said they've tried it and it did not work for them. You should give it a shot, if you want.