The Coventry-based parts supplier said the system, which was launched last October, should be achieving a million hits a month in the near future.
By value, 93% of orders are already submitted electronically.
ECAT features 250,000 product lines for more than 6,500 vehicles across 56 manufacturers, all of which are accessed from the same interface.
Pricing and stock lists are updated centrally.
Garages can report changes if information is out of date, allowing up-dates to be deployed with- in hours.