I agree witrh all the above.
I fitted the DP tuning kit that consists of a smaller front sprocket, free flow air filter, modified air box lid (its like a 1" high rim, only needd to hold the filter in place !), performance chip, and carbon cans.
That lot livened the thing up.
It was as quick as my 996 when new, but with the above it is somewhat quicker (and louder
).
I guess it depends on how much you want to spend...