"25SSK Ultimate Race Cartridge Kit - is this the best option for the front forks? I was going to upgrade the K5 forks before fitting them and wanted something as good as the rear shock."

We have two other kits that are applicable:

Front:

• K-Tech Sports/Ride day Performance Conversion
  20SSK Compression and rebound valves, service and set-up and spring. This will give you the best range for road and track use. So if you use the bike mostly on the road and do several ride days per year you can use your adjusters to firm it up for excellent Race Track performance
• K-Tech Race Bike Conversion
  20SSRK Racebike service, set-up and spring
  To take advantage of modern compounded sports tyres or slicks, this kit has the latest technology in valve design and shimstack configuration to give outstanding brake and turn-in control without harshness and provides excellent adjustability for any track/weather situation. Can be modified for Roadwork.

Rear:

• Shock Revalve Service and set-up and re-sprung
  Rear spring is good for maximum 85kg rider only

"Would the 20SSRK Racebike conversion be the best match for the rest of the bike?"

#1.  80% road, solo, sports riding, all weather, sports compound tyres, length of trip (400km) some degree of comfortable feel = K-TECH 20SSK

#2.  80% track, compounded tyres or slicks, mostly trackday = K-TECH 20SSRK modified

#3.  100% Racebike = 20SSRK Racebike, 25SSK Ultimate RACEBIKE

I hope this clarifies things for you. All of the above components offer substantial improvement in performance compared to the stock fork set-up.

The Racebike set-ups are not really a good idea on the road. They have far too much control, far too much aggressive damping, do not like cold tyres, and because of the condition of our roads, can put you into very deep excrement because of the speeds you can round corners at.