RUU will unroot, check the rooting guide.
Very few people have problems with the headphone jack. It was an issue before the maintenance release, but not anymore.
It shouldn't be sluggish either. In fact, it's entirely possible that the task killer was causing your sluggishness over time. They aren't good for your phone in the long run.
__________________
If at first you don't succeed, get a bigger hammer
Running whatever release of Froyo I happen to be on at the time 
|