You think the AS engine will give you insane performance? The only difference was in the supercharger, compared to the db-605a used in the standard g-6.
g-6/as had the top speed of 328mph on the deck, but topped out at 408mph at 27k. To compare, our g-6 can do 338 on the deck and about 395 at 21k. The g-10/as could do 415mph at alt, due to the inproved mg-cowling, bad had a poorer performance than the normal g-10 with the db-605d.