Rear window needs to be taken out to fill in the HOLE (rather large

Custom Panels quoted about $450 or so if they had to take rear window out, or less than $300 if not.
Anyone know of anyone cheaper but who can do just as good a job? I know cheap and good job don't go together, but yeah. Putting the rego on hold on the car, but still need the rust fixed - theres a lot of it (most didn't get mentioned in WoF though).