Trackdays are fun fun fun. 105db is still quite load, most bikes with normal race cans will pass that, my Honda SP1 passes with unbaffled race cans (102db) but best to take a baffle just incase.
Most tracks are mid country way, so be prepared to travel. Most of them have free camp sites on site so just camp overnight (or sleep in the back of the van).
Some tracks are harder to learn that others, but just go for Novice and you'll be fine. Theres always some fairly quick ones sharking in Novice but always some real slow ones too, you'll probably surprise yourself. If you're riding on the road at a nice pace but only using a tiny bit of your ability due to fear of crashing/road conditions etc, you may find you start to fly around the track.
It's no where near as scary you think you. Before the first session you will be scared but after the first session you'll feel more comfortable than you've never been on a bike.
I've currently got booked
Llandow 4th June
Cadwell 10th June
Pembrey 3rd July
Cadwell 4th Aug
http://www.ukracecircuitevents.com/events.asp?event_type=1&sort=1 is a good site for trackdays.