I have 18" on my touring, but getting rid of that fender gap is always going to be there, i have schinzter springs all round but the front is just a bit too high,and any lower i go the car starts to catch all over the place
10,5s on the rear sorts out all the gap issues
Undoubtedly 19s look good, it's just that 18s are usually frowned upon but they do looks good ONLY WITH A DROP OF COURSE