[yorkie_chris]

Track. You will get the benefit on track (bloody hell!). Sport one is emulsion type, biggest benefit there is you get a real spring rate... you know how well the stock emulsion shock works.

Penske is cheaper if you order from states.

Nitron look ok but I would not buy one for track use especially until I found out length and spring rate they supply. If either are stock or close to then walk away as they obviously not ridden an SV.