In my opinion, races are won in Lemons by (in no particular order):
1) Having a car that is capable of a fastest lap within 5 secs of the overall fastest lap
2) Having an average lap within 5 seconds of your fastest lap (good in traffic)
3) Having stint times near 3 hours
4) Having 1 or less black flags
5) Having pit stops that are less than 150 seconds (not counting paddock drive time and out lap)
6) No mechanical issues
(time estimates based on a 2 mile track)
If you look at the list, only #1 and #3 usually require car changes. The rest are based on driver organization, driver talent and luck.
Of all these, luck may be the most important. But as some say, luck is where preparation meets opportunity.
Teams that are capable of winning overall have paid their dues through multiple previous failures and gradual optimization of the car and team.
Cheapest way to improve is pick the brains of successful or more experienced teams. That's what we have done. Listen to and observe those who have success and try to replicate it.
Good luck!!!
Skip the wheels unless you feel you have really optimized the free stuff, but get decent rubber. It doesn't cost much more.
LemonAid - Changing kids lives one lap at a time.