Personally I would discard the Microair from any list of mine; it seems if you get a good one they are excellent value, a poor one is too fond of return trips to Australia to attempt to improve so they work properly (and fail to get better for more than 6 months).
The TRIG in all its guises is an excellent bit of kit, nothing but praise.
For future proofing the COM the Funkwerk ATR833 is excellent.
For GPS anything by Garmin if you like 'vector' mapping. Both Airbox and Flymap do nav. on a representation of the CAA (or Jepp) charts, if you prefer that. I find their smaller units unsatisfactory (very limited useful zoom range) unless used always to show you where you are on the chart you are holding. If the Garmin 695 fits your size/budget it is a magic bit of kit.
Whatever you fit will depend for reliable operation on high quality wiring and installation - don't skimp on that or your money on boxes is wasted.