I have a 1979 Tiger that I outfitted with a GTN 650 and dual G5's. I do appreciate the G5's - nice to have an HSI, and nice to remove the vacuum system. Mine has the old Century 1 autopilot, but that can be driven by the GTN/G5, so the plane will follow a GPS course pretty well.
As far as recent updates, the older AA5 models have a new AD coming out requiring inspection of the horizontal stabilizer. This was based on the failure of a stabilizer rib last year that caused a hard landing (actually kind of an amazing saved landing considering half the elevator was dangling off the back of the plane). While it looks like it won't apply to the Tiger (AA-5B), make sure your A&P/IA follows the Tiger annual maintenance checklist and performs a "tap test" to verify integrity of the stabilizer ribs.
There are some good online resources you should definitely subscribe to: Grumman Gang mail list, and at least two Facebook groups (Grumman Owner and PIlots Association, and Grumman Planes). Enjoy your new plane - it's a great one!