You prefer a close race or a sure win?
For a close race, look at the typical opponent car list and pick anyone at the middle. Tune the car to the pp point given and use the similar tire grade (sports soft I think)
For a sure win, just overpower the car, slap on race soft, turn on srf. You can also any race modified car like corvette z06 rm or Mazda furai. Up the downforce, up the horsepower (do not put in permanent upgrades else you may regret it). If you got formula gt, that's about the fastest easily controlled car to completely annihilate the opponent.
Difficult to answer as we do not know your skill level. A spec 23 does not give much info. If you were like me, new to driving games and GT, the overpowered option with aids might be more encouraging. If I remember correctly, I used Furai with srf, tcs 1, driving line on with race soft. Barely won it then.