Board Thread:Game Discussion/@comment-27109924-20160604031628/@comment-27510501-20160615114455

Upgrades definitely make a difference, but player skill is a bigger contributor in my opinion. Any two players will improve their times with a more heavily upgraded car, but a more skilled player will beat a less skilled player in the same type of car, even if it has a lower PR.

I base this opinion on the multitude of challenge board threads on this wiki... I have almost all the cars, and most have at least 14 upgrades installed. Yet I struggle to match the top players in the challenge threads in matching cars with similar PR values... The difference can only be attributable to skill.