Nothing wrong with doing them over even if you DON'T get any more money...
It's still racing, and you still get experience. These scripted 'last to first' races are some of the better challenges that the game has. Rather than barging through the AI on the first lap from a grid (either static OR rolling) and then simply pacing away from the AI, you actually, for once, have to work pretty hard.
I find the way I like to do the seasonals is have several goes at the race with a completely stock car, get a good idea, once I know the car's handling and track layout and rearmost AI's scripting, of just how MUCH I need to gain on the winner, then gradually start adding a few upgrades at a time (cheap ones first!) and gradually moving to better tires. Slowly, I get further and further up the standings, until I finally get first.
I also might start out with a few assists at the beginning (TC, ASC, ABS), and then, once I have golded with as little upgrades as I can, then start to take the assists all off, and try to gold with those without any further upgrades.
Quite a lot of challenge from just one seasonal, if not with any extra payout. Payout is pretty over the top, anyway, so even if I have to run the race quite a lot to finally get gold with all assists off, I feel I got my effort's worth...
I simply wish the game had an easy way to take upgrades OFF. In real life, you buy a weight reduction, you can easily add weight back, you upgrade your engine, you can remove the upgrades etc., etc.. Sometimes you can overcook adding upgrades and find it a little TOO easy to get 1st, and there's nothing you can do to remove them, you got to buy a whole other CAR to get back to where you were. This is INSANE!
But, especially because you aren't grinding boring races for points, you can stretch quite a bit of use out of the seasonals, even if you DON'T get more money after you gold the first time...
