I have just put on new coilover last week, however, I just realized one corner sits lower than the other 3. Did I cause any damage to my drivetrain? Thanks

Did you try adjusting the CO on that corner?

I will but, can't seem to find the coilover adjustment wrench thing. Is it gonna damage any part of the car if I just leave it as it is until I can find the wrench or buy a new pair. Thanks

I bet you're going to ruin your tires in a jippy. I would even them out ASAP and get your wheels aligned unless you have an unlimited tire budget.

So no real damages to the drivetrain and anything else other than the tires right?

no. no problems. the axles have CV joints for that reason. also, the differentials keep things from messing up when one wheel spins faster then another... so you'll be fine drivetrainwise. tires on the other hand can be screwed in a jiffy just like yellowman said. as me how i know, one day is all it takes, i'll send you a picture if you want :P