The acura motor will not work in the civic. The motor mounts are not going to line up unless you make some custom mounts. Either way the motor will only give you about 4 more hp over the motor thats already in the car. The A6 can be built up to a very impressive motor. I would suggest FI but if not you can use zc pistons and a exospeed cam to really get the car moving with little cash. The head swaps are alright but the A6 head is a very nice piece also.