well...the crx was pure racing engine....which has only one job...to last heavy pounding at high rpm and high rpm only....
so basically anything lower than 4k rpm powerband wasn't helpfull at all..to save weight and less mechanical part to fail why not just disable and remove the vtec mechanism all together...
i think they choose b-series and turned it into carbie monster because of the engine already "race worthy configuration" plus no electronic programming, making carbie tuning a simple and easy power choice....