Will wheels from a 2016 RX350 fit a 2008 RX350? The originals are 18x7.0/5 i believe and the new ones are 18x8. Any input would be greatly appreciated, thank you.

I'm going to guess they will. Tirerack.com is a good place to get specs for wheels. As long as the bolt pattern is the same, and offset is close/same, they should work.

Put in your RX and look at what info is available. Do the same for another year. It will show the bolt pattern and offset.

The rims are normally the same and can be crossed over.

Tires can be wider and will fit existing rims. Some people have opted to go 1 up, means wider, but will the adjustment on the height as well. Tire Rack can help you understand.

The key is the combination of the width and height must be addressed so that the effective diameter of the tire remains per OEM spec. Means 1 full rotation of the tire is the same distance traveled by the car, so mileage and speed accury are maintained.

You are referring to plus 1/plus 2 fitments and it's based on the aspect ratio of the tire. In, for example, a P235/50r18 the 235 is the width of the tire sidewall to sidewall in millimeters (25.4 millimeters to an inch) and the 50 is the height of the sidewall as a percentage of the width (in this case 117.5 mm or 4.6 inches.) The 18 obviously wheel diameter. By using this formula you can easily determine which tires, based on outside diameter, will fit. In the case of this tire it would have a rolling diameter of approx. 27.2 inches (4.6+4.6+18.)

Offset and clearance to the strut and fender well are separate issues.

Tire Rack has all the options possible listed. Safe combinations.