the cvh manifolds are shite, so a 4 branch and decent exhuast might give you a little less low down grunt, but itll pull alot better all th way to the redline. k+n wont make any noticable difference on the road other than itll sound a bit better. piper 285 cam with give you a decent increase in performance right across the rev range.

if you can get hold of a webber DMTR carb, twin choke jobbie fitted as an upgrade to the DFT, itll make a nice difference in performance too. real nice carb to drive with aswell as you get a major kick up the arse when you open the 2nd choke!