I’ve flown a lot of Malibu’s over the years and seen lots of avionics arrangements. In some airplanes there are unbelievably expensive “glass panel” updates and some (like my previous radio stack) had a KLN-90B only.
The Malibu I now fly regularly has one of the better combinations of cost/amenities. The Garmin 530W for communication and navigation is really hard to beat. I also have the Garmin 430W, but I rarely, if ever, use it. It’s ice to have an additional radio, but not worth the money, in my opinion. The problem with the Garmin 530/430 is that you’ll need a very expensive ($5,000+) box added to your airplane to have downlinkable weather displayed on the Garmin 530W. This is easily the biggest issue with the 530W, in my opinion. However, there is a cheaper option…
The Garmin 496, although not IFR capable, is great because you can display downlinkable weather. My aircraft has an Airgizmo installation which makes the unit easy to remove from the panel and also tilts the display toward the left seat. It is a really easy GPS to operate and the redundant GPS information is comforting.
Yes, there are bigger, better, and fancier panels. However, this is what I fly regularly and I find it to have a lot of “bang for the buck”. For a guy that flew both the crappy old KLN-90B and super-nice glass cockpit installations, this is what I’d put in my airplane if I were the owner.