The AS-03 is an ultra high performance ALL SEASON tire, the BFG Sport Comp 2 is a SUMMER tire (although my early production run models are labelled as "M&S", due to meeting that designation's 'land to void' criteria).
If you want to compare a BFG tire to the AS-03, use their g-Force Super Sport all season.
I have BOTH of the above BFG tires on separate wheels, and LOVE the way they handle and stick, brake, and transition,
especially for 340-400 treadwear rated rubber.
They are owned by Michelin, and there must be some transference of performance technology between the two companies.
The ONLY complaint I have with the Sport Comp 2 is the ugly (to me at least) tread pattern.
But then, they would NOT be the great rain tires they are with a more pure dry performance oriented, more slick-like, big tread block pattern.