In honesty, you will have to install more than just a G5 in order to obtain the full utility of the GNS480 / CNX80. The really good navigation guidance comes in the form of an ARINC 429 digital data signal which the G5 cannot interpret natively - it requires a GAD29 to do that work.
If I were in your boat I would likely default to installing a GRT Horizon EX or Horizon 10.1 EFIS with the ARINC 429 module. This will give you the ability to use all the GNS480's capabilities while working with a larger format display, one that gives you a lot of options including the ability to add mapping, engine monitoring, etc. The G5 is a fairly small piece of glass thus its feature set is somewhat limited as compared to other EFIS product offerings.
Yes, I'll admit to having a bias. My panel consists of a GNS480, SL30, Trig TT22 transponder, PS Engineering audio panel, a TruTrak Vizion 385 autopilot and three GRT EFIS... A Mini-X, a legacy HX and a new Sport EX, with engine monitoring via the GRT EIS-66R remote engine monitor. This solution works for me because it's so simple to use. It is a very infrequent thing for me to have to push buttons on any of the EFIS screens. I love seeing the vertical and lateral guidance from the GNS480 showing up on the EFIS screen as the autopilot keeps the needles dead center on an approach.
EDIT: while writing the above I failed to recall that you have a TruTrak autopilot. Depending on which one it is, the GRT EFIS products will likely give you the very best probability of obtaining full functionality from both the GNS480 and the TruTrak autopilot.
