noob wheel question

I've just bought some 18s for my mk4 ls400 
Problem is they catch the front calipers 
How much can I trim off the calipers 
The wheels are et 35 and I don't like the idea of spacers
Cheers russ

Go and get some thin spacers to test out how much more clearance you need in the first place....

Also: Why do feel the need to run those wheels?

Look on Gumtree and see if anyone in Yorkshire is selling some used spacers. If you really feel you need to run these wheels, get some longer wheel stud and go crazy. Otherwise, different wheels.

A 3 or 5mm spacer is better than shaving 3-5mm off your calipers..

Shaving calipers is dumb IMO (unless they're Z32 brakes as you just shave off the nissan logo)

Run spacers or buy the correct disk to fit the vehicle.

Yah dood, spacers is the way to go, much easier too. 
Which option is safer? That could be an interesting discussion.

Get spacers or change wheels.