Interesring that this thread came back to life. So now the rest of the story...

I did buy a Garmin 320 but never installed it. I later picked up a Microair T2000 for a good deal on an insurance salvage auction and installed it in the Cherokee. It works really good and I use it often to get radar service from Wichita Approach and occasionally fly in or over the Class C.

I liked it so much that we bought another T2000 from Europe and put it in the Std Cirrus. I've also spent some time in the Class C in that glider as well as getting radar services from Longview (Texas) Approach on my way to Louisiana last April.