Followed a similar route upgrading mine to Simon. We got our RP23s from Merlin for £150. In my opinion it has greatly improved the feel of the rear suspension. Much plusher yet controlled with the pro pedal off. It now has that bottomless travel feel.
With pro pedal on it rides like a hard tail with plenty of rear end grip.
I have changed the forks to Magura Thors, wheels to Mavic Crossmax STs, Hope Tech M4 brakes and a full XTR drivetrain.
Brilliant bike which I wish I had the time to ride more in suitable terrain. Set in the FR setting permanently now.
I can’t agree with this comment from above by Marran with regards to air shocks, coil yes –
“Off the shelf dampers will probably not work well at all”
The RP23 is off the shelf and as already said does a brilliant job.
Suffice to say it will not be sold anytime in the near future.