The Adam Drake 2 is a great kit out of the box. The only uprades I installed were Rock Concepts front carrier and rear pivot block. As for the engine, I believe Drake still runs a Sirio Evo 2. I am pretty sure you can no longer buy them because Sirio is realeasing the EVO 3. I personally run a Sirio Adam Drake SE and an OS CVR depending on the conditions (both side exhaust engines). Honestly, I usually post faster times with the OS because its power is more stable than that of the high horsepower Sirio. When you put those high horsepower rear exhast engines in a 2wd STADIUM TRUCK, you run the risk of spinning you tires the whole time. Rear exhaust engines, like the RB V12 and OS TZ, are only good on high traction blue groove conditions. If you want to be fast start with the OS, learn how to be fast and consistent with it, and then put that fire breathing Italian engine in it. Just my two cents.