I decided to re-do my panel over the winter to accomodate an iPad mini on the right side of the instrument panel. The central radio stack had to go. Here is the old setup that served me well for 14 years:
Here is the new panel:
The only new items are an MGL V6 comm, a Sandia Aerospace STX -165 transponder and fuse blocks behind the fold-down door on the right. Net loss of seven pounds from the empty weight.
I've got about 10 hours on the new radio and transponder and I like them both. The transponder was dead simple to wire for my simple installation, +12V, a ground wire, static air connection and an antenna.