BE35 pilot reported an engine and electrical malfunctions during cruise in an area of IFR weather while in VMC conditions. The pilot proceeded direct to the destination airport and landed then determined the electronic magneto had failed.

Narrative

We departed ZZZ around XA:00 local for a flight home. At the time the weather around ZZZ1 was IFR; but forecast to be VFR by XB:00pm local. Runup was normal; takeoff and climb normal.Flight proceeded as normal until around the local town. I noticed that the engine was running rougher than normal and my EGTs were much higher than normal. I suspected a magneto failure.I was about to contact ATC when I noticed that my transponder had a message saying it had failed. I thought this odd as I had been receiving ADS-B traffic and weather the whole flight.Since I have an electronic magneto; and now noticed another electrical component had failed; I had a strong suspicion that I was on the verge of experiencing and electrical failure. I started turning off all non-essential components and proceeded directly to the IAF for my home airport. It appeared to be IFR everywhere within fuel range; so I did not want to depart over higher terrain on one magneto and not knowing if a total electrical failure was imminent.Not wanting to use any more electrical power than absolutely necessary; I lowered the landing gear by hand and turned off everything except my backup PFD (Primary Flight Display) and proceeded to fly the approach to a successful landing.Upon landing I checked and my electronic magneto was completely failed.