Yes, have been wondering about that...have hangar neighbor with UL powered Zenith, loves it.
Are you flying with UL?
I assume you had to go E-LSA to do it.
Not flying yet, but I have the engine, UL350iS, mounted and just finishing up the cowl fitting. I'm hoping to be flying soon...that's a relative term.
I think you mean, "go E-AB", and that is correct. While there is an endless amount of opinions and threads on this topic, I don't personally see it as a big deal; especially for the benefit I get by customizing my build the way I want.
Although the first engine mounts and cowls had development issues, there is now a solid engine mount and cowl setup available for the RV-12 and a UL engine. You may want to consider the UL260iS as it's 107hp and just a couple pounds lighter than the 912ULS. There is a group of us that have gone the UL route with some collective knowledge we can share.
I'm a bit of an outlier in that I went with the 350iS, which has more hp and torque, but weighs about 9 pounds more all in. I had to do some engineering and work with the UL both here in the US and Belgium, but I'm very happy with my setup now.
Although 10 pounds of the engine weight is fuel pumps, filters, ECU, VR and coil packs (none of which are attached to the engine, but rather elsewhere in the aircraft such as the FW, instrument bay and back at the fuel tank), the suspended weight of the engine is 159 pounds complete and very comparable to the suspended ~160lbs weight and balance for 912.
No carbs, magnetos, gearbox, or coolant system....just a simple four cylinder engine. I can say it starts on the first blade pass and runs very smoothly with a nice baritone rumble. I'm holding off on saying much more publicly until after I have firm performance data...hopefully in the next few months.