Time for an update: In the end I went for the double sided Lextek system with the XP8c silencers. I think the whole setup weighs in at 7-8kg compared with the OEM lump which I measured at 15kg. I also bought the Lextek rear sets (I weighed the stock foot peg assemblies at 3kg in total) which are impressively well made for the price, although be prepared for a bit of head scratching since no instructions come in the box. I also stuck on an Evotek tail tidy - really good quality, and as a bonus some instructions are included!
Today I went over to Junction 33 (https://www.facebook.com/DynoDude/
) near Lancaster to get a Woolich ECU reflash done, and a remap on the dyno after fitting the full exhaust system - I could sense a big fat flat spot. Andy who runs the place is a top bloke and it all went smoothly - it was a beautiful day and I had a great run back over the Forest of Bowland. The bike feels brilliant after, smooth, powerful and basically more fun. Results attached (15%, 30% and full throttle before and after) and you can see pictures of the bike on Andy's facebook page at the link above.
I also sourced a YSS shock with remote reservoir/preload on Ebay from another really good bloke who pointed me in the direction of an excellent suspension guy who sorted out my forks with Ktech springs (0.95Kg/mm), 5wt oil and a revalve. They now have lots of adjustment and feel a lot plusher. He also removed the hydraulic bump stops to effectively increase the fork travel.
I'm really happy with the results, and it's made a 4 year old bike that needed a bit of TLC feel like a lot of fun again for a lot less cash than buying a new one!
Last few jobs: remove the lambda sensor, remove or plug the pair valve to reduce the exhaust popping on the overrun, and maybe buy some of the Speedymoto Tall boys risers for a better handlebar position - anyone else got them?