The ADS-B out feature is a whole lot more difficult than ADSB-in.
ADS-B out is a transponder function. The transponder can transmit on one of two frequencies (in the US). It needs to be able to provide mode-S location information, which means it needs data from a GPS and I think also from a blind encoder.
The transponder in my plane is certificated, as is the blind encoder. If it were to install a transponder with ADS-B out it and the GPS would have to be certificated.
Garmin and Trig make suitable transponders. I don't know if a certificated blind GPS is available but the Garmin 430 WAAS or the newer units can do it. If you had that you'd probably have TIS and would not care about the SkyRadar for traffic.
The SkyRadar is primarily a weather solution. If you need traffic (beyond the "it would be cool" level) there are better ways to go.