The Novarossi Sturm is a very capable engine. I race one in our local club series against more expensive engines. You do notice there is a bit less power, but in laptimes there is hardly any difference.

In the German HobbyCup they use the Sonic PS 12 or Xceed PSS 12, both Picco based. I have not seen them run, but from what I've read, they are comparable to the Novarossi Sturm engines.

All three seem very suitable for a spec class. They match current chassis quite well in terms of clutches and RPMs. Judging from the specs, the TG runs a lot less RPM, so I wonder if you can really get clutches, gearing and 2-speed right.

http://www.sonic-engines.com/index.php/products/ps12
http://www.mrt-rcshop.de/XCEED-Hobby...oStock12-PSS12