I just had my first "easy 200pt win" yesterday. I took my '98 Impreza STi 22B (bone stock, still on the Sport Medium tires) into the "Normal" Tsukuba Wet race in the Special Conditions hall. Opponent was a Mercedes SL600 and they rated the race at 200 A-spec points. I caught him in the first turn and walked away from him for the remainder of the 3-lap race.
I've also lost single-digit point races, though, despite giving them everything I've got...so the formula is definitely not perfect. (I guess they don't figure in drivetrain differences on Tsukuba Wet as part of the formula as I'm sure the AWD vs FR traction difference is the primary reason I won that race so easily.)
I like the idea of A-spec points for gauging the difficult of a race, but they need to make three changes to make it actually useful:
(1) Work on the formula to make it a bit more accurate (I know it can't be perfect, but it can obviously be better than it currently is).
(2) Show you the possible range of points before entering a race (for example, it could state that based on your current car setup, you would get between 15-30 points for this race depending on which cpu cars the game selects).
(3) Get rid of the "ringer" / illegal car issue as this would make #2 useless. (In other words, the car that is notably faster than the other randomly chosen CPU cars but doesn't always appear (e.g., Shelby Cobra in the European 1000 miles race) or a car that player is not allowed to use as they don't meet the entry requirements (e.g., Cadillac Cien / VW W12 Nardo in the Pro. Hall Supercar race).)