Thankyou. I was planning to do as many trackdays as i could to learn my bike. Is it possible to adjust the fueling on an 04 620ie Monster without buying any add on's? Ive not got an off the shelf exhaust though, will this make it more difficult?

Dyno time will be the way to tell, and it isn't that expensive - it's the hours of fiddling which is the expensive bit! There's only limited ability to weaken or richen the mixture and this is through the range, but you may find that the bike runs fine if it gets setup (reset) properly.

I'd get a simple power run done, see what you're getting and what the fuelling is doing thru' the range. The exhaust could weaken it up a bit at the top end.
The PC is good for the finer tuning but you won't get a lot more power, if any, for £'s spent, just finesse :)
Track time is key as already said, and if suspension improves the experience then spend your money there.

some one told me a great tip on this borad when i was preparing my bike dont mess with it untill you know you got a problem. i asked a lot about the frount suspension and now it clear to me after racing at cadwell i need progressive sring in them but first im going to try just replacing the oil in them.

the work i did to my bike (583) was add scopion race system, kand n filter and a usual service i.e oil, filter new spark plugs, new belts and then braded brake lines frount and back and ecb double h pads i also had it run on a dyno and after one or two runs the guy said if fueling perfect dont mess.

i also learnt from cadwell just how hard you can brake into a corner so iv just spent £60 on ebay so i can up grade to twin brakes on the frount.

so my advise is to just run it and see could save your self some money