There's a huge variance in the actual width of tires listed as having the same section width.I have 245 width Pilot PS2s on my 9.5" wide wheels,and they'realmost square fitting.Scott had some 255 width Dunlops on his 9.5" wide wheels,and they were much more stretched than my 245s.The section width is measured at the widest point of the tire,and many low profile tires have rim protector lips that stick out 5+mm right at the bead of the tire on both sides,so this can be well over 10mm wider than the width of the useable part of the tire,and that's how the tire is spec'd.The tread width is a better way to judge a tires true width,although some manufacturers don't list this spec.

Anyway,you've already ordered the wheels in 8.5" width,so it's not really important now anyway,haha.With the power you're making,obviously all the rubber you can get will help,so it's something to think about in the future.You can get a 245 width tire that will have a tread width up to 20mm wider than others,so it can make a big difference in traction and fitment.
I'm not sure what wifth wheels/tires come stock on the 135s,but you can usually gain at least 20-30mm more width without having fender lip issues or requiring any rolling of the fenders since the manufacturers are very conservative in leaving plenty of room on the inside and outside.

I really like those particular VMR wheels,and I think any color other than black will look much better anyway.Modbargains had a great sale on them around Christmas,and I wanted to get a set,but didn't have the cash at the time.Excited to see them on the car!