Rule of thumb: If you want a Lb/Ft. torque rating multiply the torque figure by 7.
I believe that I got that little gem from
Famine, the knower of all things GT3.

ON the quest for "GT3 domination" Go back thru the lisence tests and look at the demos and try to emulate them to the best of your ability. This will teach you how to be faster.
As for making in money and winning cars...
My money making race is the European cup and the German car cup in Amatuer league.
With each of these series if you save after the fourth race you can either run the last race repeatedly, by reloading, until you get the Vertigo or the Astra (respective series) as a prize car. They are both very good cars in their own right, but have a resale value of 300,000 and 245,000 respectively. Great vehicles for padding the coffers with cash.
I would personally steer you away from the Escudo and the F1's for normal racing. There's a reason that you don't win the 'Scud until the
end of the rally races. Just as there's a reason you don't win an F1 car until you've beaten some fairly "strenuous" races.
As
SnowBordrWRX has said you could win these cars and just Spank the competition in the rest of the game. But that's not gonna make you fast. It'll just mean that you're smart enought to have brought a "Shotgun to a knife fight".
Real gratification comes in this game when you've showed up "empty handed to a knife fight" and emerged victorious. For example, when you beat the PD cup with an Elise or the baby Tommy Kaira. Or when you take the Amateur Type R cup in a mildly tuned Civic Type R.
Then when it comes time to race in the all Formula 1 races, you will be better prepared.
There is also a ton of info here at this sight. Do a Search for "compendium". You should find
Der Alta' detailed write-up for how he completed the entire game. It isn't the fastest path to completion of the game. It will show the path that will cultivate your skills as you race thru the more difficult series and single races.
Good luck, Enjoy, and Welcome to the Planet.👍