Is this thing free? It would be a pain to replace the whole thing, mostly the adjusting part.
Have you considered just buying a new top and the accessories? Cost me about 500 to do it myself and 3 days of work (1st time). About 300 less than I could find with someone else doing the work. It was not hard, just took a long time to trial and fit everything. Not as good as a professional, but I like the challenge.
The only thing I had to get was the air stapler that would fit the proper staples.