What about a Garmin 430 if you're already to a 420.... 430 adds a nav built in...
Of course, in any case, always back stuff up! I had a 430 lock up on my before during my commercial training, was shooting a VOR approach and the needle was centered, had the other radio tuned in and saw them start to deviate. Everything seemed fine from a radio standpoint on the garmin. You could change frequencies and ID the station etc, but we realized it was partially locked up when messing with it... weird failure mode.
It's always good to back stuff up anyway though.
Something else: an HSI in place of the DG and an RMI for the ADF indicator is a wonderful addition. We have an HSI and RMI on each side, they are incredibly useful. RMIs have dual needles so you can have two VORs or a VOR and NDB or two NDBs tuned in (we have a few planes with dual ADFs) and see relative bearings at once. The HSI can really help your situational awareness as well, makes it incredibly to see what your intercept course is to a radial or ILS and you can do back course localizer without having to worry about reverse sensing.
As far as IGS approaches go:
I said it in chat, but forgot to here, I did find an IGS into Lugano. There may be more than one but that one was an ILS with an 8.1 degree glideslope! It also had some pretty stringent climb gradiants to be able to go missed. I kind of don't have the link now though because I shut down the computer since then (oops).
So apparently the "IGS" approach is alive internationally, and seems to indicate an approach which has large deviations from standard and special requirements (IE larger than normal decent rates or large angle from approach course to the airport), but I still don't have an official definition of what IGS stands for and what makes an approach an IGS. Both IGS approaches found thus far were ILS based approaches.