Hi Adrian, and welcome, K2's are quite easy to restore, parts are all over ebay, many people are restoring these bikes to mint condition and selling good used parts with that hard earned patina at a resonable price , Dave silvers is selling repro exhausts now for this model at a great price, saying this it is still quite easy to spend lots even on a non show bike, i spent loads of money on my F2, far more than it is worth, and that was just restoring it to a good used condition with original paint, and lots of secondhand parts,
Pete