To use the Concrete Limiter route the incoming audio to a track with the Concrete Limiter enabled and set the output (or better a send) to another track via a patch point (this could be an aux track).
SONAR records the input signal. This is true for all track types. It is the reason why regular audio tracks record dry. However, input to patch points may be an affected signal from another track. When using this technique consider recording both the raw and affected track, just in case.
The problems with recording software FXs include latency and the inability to remove the effects after recording. Of course, this will not do anything to correct too hot a signal at the interface input.