Tire size?
 

I got 18x8+45 wheels and am not sure if I should run 225/35/18, 225/40/18, or 235/40/18. I want to run 235s but am not sure if It'd be too large a speedo error. Thoughts?

Definitely go for the 225/40. The 235 is an option, but it’s a bit too tall if you ask me. 225/40 is perfect for the 8 inch wide wheel

Speedo error would be ~3.1km/hr on 235/40/18.

100km/hr= 103.1km/hr with those.

Isn't height the (40)? So you're saying the wheel will be taller at 235 width as opposed to 225? Also, should I go 225/40 or 225/35?

It's aspect ratio, not height, it varies with width, a 215/45/17 is the same diameter as a 245/40/17.

225/40/18 is a very common size. You’ll be able to find a good variety of tires for good prices. That size is under a 2% difference from stock and the speedometer will be about like 1.14mph under your actual speed I think. 235/40 is a 3.2% difference and the speedo will be almost 2mph under. I’ve seen people even running 215 on an 8 inch wheel too, but it’s up to you. I’d just take the 225/40/18. It’ll look good on the wheel, you’ll save some money, and it’ll be lighter than the thicker tire