You should be careful when using wider wheels.

What does an offset of 40+ mean? The offset is a specific number of millimeters.

you can find info on the internet on how to measure offset. The hard part is having a straight edge of the proper length to span the wheel edges if there are tires mounted on the wheels.

Wheels that are too wide may rub on something. On our 744 turbo, the hydra wheels that came with the car rubbed on the wire to the antilock sensor on one of the front wheels until the wire was worn to its center. On our '96 855R, the wheels were so wide that the car had special front fender liners that were cut away near the shock towers so that the tires would not rub.

Volvo actually built the car with wheels were too wide for the car without special parts! If you put those wheels on a regular 850, the wheels would rub all the time!

Also be aware that wide tires are much more sensitive to tire pressures. If your wheel or tires have a slow leak, the problem gets serious more quickly.