Looking to borrow a pair of known-good 17" or 18" wheels/tires for further troubleshooting?

[Jlaa]

I've been trying to hunt down some micro-vibrations in my car for some months now.
I have had my wheels/tires roadforced balanced many times now, but I would like to rule out the wheels/tires once and for all.

Might anyone have a pair of known-good-smooth-riding 17" or 18" wheels and tires I could try fitting on my car?
I ask for this size because my brakes in the front preclude the ability to fit 16" wheels/tires on the car.

Thanks.