Heres the thing...... exhaust is preference....... you go with what you like, you go with what puts a smile on your face, no one can tell you what to have on your car.... ive been through rotary exhausts, race pipes, cat backs,midpipes list is endless, Ive had the K1 and i didnt get fed up of it at all.... people say about the cabin noise etc you wanna try running a rb20 or having a bridgeport or streetport. Put the bungs in on the K1 the noise inside is fine. My K1 has/was been fitted perfectly heat wrapped in the necessary places so no rubbing however AVOID there decats very poorly fabricated.
Learning how to shift perfect also works wonders. you could easily spend thousands on a set up and still not be happy, grab a budget and be patient i guess good luck hunting.
RaINE