I had an Electroair EIS-61000 fitted under STC to an SR22. Best thing since sliced bread. Probably didn't recoup the cost in fuel savings, but in terms of the intangibles - easier starting, rock-steady performance of the EIS, worth its weight in gold. Cost about US$5k + EO. The EIS replaces one mag and sparks 15,000V cf 1,500V a mag produces, so essentially the EIS is doing all the work while the second mag is just along for the ride, or if the EIS fails - which is less likely than the mag failing as the EIS is solid state vs the mag with it's bunch of parts rotating constantly like a washing machine.
And the best thing is you have a spare mag which you can then use to replace the other mag when it eventually does fail, while the EIS keeps happily humming along!
Feel free to PM if you'd like to discuss off-air.