Yeah you will basically have to align the housings back up to get your gaps even etc. tightening a couple bolts to hold it in place and doing that solo isn't going to be easy.

If your E70 is pre LCI you will have to remove the black plastic portion of your front bumper as its clipped into the fenders under the lights. Once you do that you'll gain access to anything on the lower section of your fenders but I know for sure there's bolts (think 3) going up/down along your door seam/hinges area (so you need to open the doors) plus the ones that run along the top of the fenders in the engine bay.

I'd just tape everything up and leave it alone. If you have a compressor and an air hose next time you wash the car get it really wet in there and compress air what dirt you can get out.