In general, a monotube shock is going to be a better performer for longer than a similar twin tube for a couple of reasons. 1) a mono-tube is using a greater amount of the internal area of the shock for fluid control, hence minor adjustments will have a bigger impact. 2) Twin tube shocks have the tubes isolated from the shock body so they are not as efficient at disappating heat as a mono-tube that can pass heat directly through the shock body.

However, for most street driving and even autocross, a twin tube of a good design, especially an adjustable one, will deliver a huge gain in performance over a junk designed mono-tube. For sustained high speed laps or competition, a well designed mono-tube or remote reservour design would be needed