It's a good game and I don't have many problems with it either but I do have some problems with it.
-One, not enough cars. That's the only that will change as the game ages and if they add more cars.
-Two, very little visual customization. This goes along side number 1 with the same argument but there is a decent amount of customization but I wish you could remove body panels to make drift missiles and there should be more head light and tail light mods.
-Three, I don't know if pc is the same but the running is finicky where it will stop running all together or go back and forth.
-Four, there should be a crouch button. Again idk if it's different on pc but on console you can't crouch which is annoying when you want to reach something or get stuck ( yes if the lift is just low enough you can get stuck ) under the car while it's on the lift.
-Five, engine swaps. I was swapping a v8 into the s13 where it had a I6 before but when I built the v8 it said it didn't fit and I was confused cause I thought I had taken everything out the would have conflicted with it, but no I forgot to remove a portion of the exhaust before putting it in. Now my problem is that the game doesn't say that you need to remove that before putting something else in. It just gets mad.
I might add more if I find more things but that's all I had found annoying.