Had a OS .18 in mine for about four months.
Replaced it with a Dynamite .12Spd to race gas truck.
It was kinda odd the .12 was faster than the .18 on the track!!!!
BUT on the street or backyard the 18 was faster AND I needed a wheely bar for the street!!
Got the Dynamite .12Spd because my brother raced at the Vegas 2004 Off Road race and stayed with Adam Drake down the long back straight witha Dynamite .12Spd!!! Never came close after the first turn!!!
NO engine makes up for driving skill!!!!