I have a GTX 330 installed in a Baron as well as an Extra. In my opinion it
is one of the most valuable avionics upgrades you can buy- it's simply
amazing how much traffic is out there that you never pick up visually, even
with a good scan. Definitely worth the investment, which as I recall was
around $3500 installed.

If you ever get a chance to fly with one you'll be convinced immediately.

Good luck.