Any tips or pit falls when narrowing a front beam on a 1970 1500 beetle?

[paulgrey]

Hi I am looking for advise on narrowing the front beam of a 1500 1970 beetle, I have to narrow it to fit a new set of 18" wheels. The narrowing is to stop rubbing from the wheel onto the strut tower... I figure once I have narrowed the front beam I can then space the wheels out a little... Is doing all of this going to effect the suspension of the car?. Is there going to be problems with shorteneing the sway away bars?.