As other have said avoid the Garmin 328 or you will be replacing it in a short time. No ADSB Squitter.
Also I had your line of thinking with the SL30 when I built my Sportcruiser, but wouldn't do it again if I was building now...the VOR for nav purposes will be defunct in a few years and you can't fly an ILS on a LAA permit aircraft currently anyway. Save the money and buy a decent EFIS (not Dynon Skyview).