You never said anything about your old shock being worn out, you asked about the difference between a stock 08-11 vs the 12+ balance free shock.
'06 F4i: racetech front springs+valves, ohlins rear shock, steel brake lines, 'mura slipon, 89K miles
'08 600RR- steel brake lines, shorty brake lever. Stripped track bike.
'15 1000RR- Flapper mod, 08-11 gauge swap, hotbodies fender eliminator