Hmm, maybe only a little..
Need to focus on your power goals, it's easy to become wound up in the "I need a bigger this, and i need 10 more of that!" mindset
If you have a goal, and your current *insert part name* will suffice (even if only just) then leave it be.. You can always upgrade at a later stage for that extra few ponies.. Most important thing is to get the car completed and sort the bugs out.. And then you can tweak and upgrade imo