This is a good resource for the A700 -
http://racerlog.com/wiki/Awesomatix_A700#Current_Models
With my cars on the track with identical settings - the case usually comes down type of powerplant/class.
The L feels like it is more free and nimble than the EX with 17.5 blinky. The EX feels more at home in 13.5/10.5/mod trim - stability and cornerspeed.
IMO - the EX will provide a larger range of tuning options and provide a better range of drivability irrespective of power options.