Not spending Points on car.

Yes. It's quite logical why, too. The research gives a percentage of the difference between the stat of your car and the one of the best car in that stat.

For example you're 10 points behind in acceleration and downforce and researching those 2 stats would give you 35% each. So 35% of 10 would be 3.5 which results in 4 design points each stat, 8 total. Now if you'd spend 2 design points on each of those stats, the difference gets reduced to 8 points and research gets you 35% of 8 which is 2.8 and results in 3 points each, 6 total. So by waiting you get 2 more design points but of course your car would be slightly less competetive for that race.

So it's finding the right decision for the given situation. In that example above you also could spend all 4 points on one of those stats, so it'd be 4 points research in one stat and 35% of 6 which is 2.1 and since the game always rounds up that results in 3 points for a total of 7. 1 point up from splitting the design points and one point less than saving them.