I'm kinda surprised these are still even available new from the dealer.
I'm in the market for a replacement for my Si as well, and from what
I've found so far, any used unit that you find that's in very good,
unbroken condition is probably going to cost you more than $200. Then
you'll find the ones that have broken but have been repaired with
varying degrees of skill. Sometimes the ones that only have a couple of
cracks can be repaired with epoxy, but $300 for a brand-new one doesn't
sound like such a bad deal once you've seen a few Frankensteined units.
Check ebay, or if you're unbelievably lucky you might find a usable one
in a parts yard. I'd bet that the chances of finding an uncracked one
there are probably about as good as finding a set of factory floor mats
- not very good.

There's one guy on ebay who claims to have modified another unit to work
in CRXs, but without having seen the results, I'm skeptical.

Honda really screwed the pooch with the panel design of these control
units. I have yet to encounter a longtime CRX owner who hasn't had to
deal with this issue at some point.

Dave