to be fair, lots people say the rear shock is a weak link on the the EVO. IMO if you are paying £400-500 for a new rear shock to improve handling you might as well get the forks done too and feel the full benefit.
Some complain that having to re-suspend a new bike is not acceptable but if you consider the range of sizes and riding styles a new bike needs to cover then you can imagine the standard set up on most bikes will be lacking.
Black Bob had a new shock on his and he seems to think it transformed the bike