Bravo, you've done your homework
Both setups net similar fitments w/ the top set being about 3mm further in on the front, you might consider 255s in the front if you go w/ that setup since the 9.5" will be a bit stretched w/ 245s. Have you verified Big caliper clearance w/ the Rennens? Always nice to have your new setup that clears a BBK, as you may want to get the big Akebonos down the road.
Other than that you should be good to go, those gramlites are a pretty hot looking rim IMO.
If you don't mind rolling your rear fender edge you could get 285s back there too

 

Recommendations accepted. Thanks Blnewt!! Edited my original to update tire sizes. Still open to ideas, opinions, recommendations.

 

I'd only go w/ the 285s w/ a fender roll, I think the 08 coupes have a flat fender edge compared w/ the rolled fender on the 07+ sedans but could be mistaken

 

The rear on the '08 Coupe does have a flat edge on the fender. What do you think of the Rennen CSL-2 sizing/configuration. Appreciate the help. The set-up I described above is going for $1375.

 

The tire width sizing & offsets are spot on, not sure about the 19s in front 20s in back. I've seen a couple setups like that but don't have any fresh pics for comparison. It would probably look pretty good if you went 275/30/20s rather than 275/35 in back, this would keep the sidewalls the same thickness front to back, a slightly larger diameter tire combined w/ a slightly larger wheel may look a bit off. Hard to say without seeing a pic of that exact setup
And again, those Rennens have a pretty good lip and those aren't always able to clear the big calipers, that would be my main concern w/ that set. This template is useful if the vendor can't verify clearance
http://infinitig37.com/tech-images/akebonotemplate.pdf

 

Need some advice on fitment and tire sizes. I recently bought a set of used Stance ST-1's

20X8.5 +35
20X10 +38

With my research, these should not rub, is that correct? What would I need to do to make these flush?

The front two came with new tires but the rear's are bald. I was considering 275/40/20 or 285/35/20. I'm at stock height and don't plan to lower until next spring. Which tire would look the best, I'm looking for meaty tires.

 

Coupe or Sedan?

 

coupe, non-sport

 

The 275/40s are way too tall, by almost 2" for a whopping 6.7% taller than OEM, for RWD 3% is considered the most variance you should shoot for.

The 285/35s are better but still almost 4% taller.

That's the tradeoff for going w/ larger diameter wheels, the tires sidewalls have to shorten to make up for it.

FWIW a 275/35/20 is right at 3% so about the "meatiest" tire I could recommend.

BTW, what front tire size are you running?

 

245/30/20 up front

 

Hmmmm, I can see why you'd want some meatier tires, those fronts are about an inch smaller in diameter than OEM
Proper size for 20s would be 245/35 front & 275, 285 or 295/30s in back for staggered sets.

 

Yea, I'm going to go with 275/30. What would i need for a flush look? any spacers?

 

I'd go ahead and get your tires mounted up then decide exactly how much spacing you want. What may look "flush" to me may be different than what you prefer. Here's a good vid clip on measuring for spacers. FWIW I ALWAYS recommend getting spacers after you get it set up as it's very easy to install them later compared to ordering the wrong ones and dealing w/ returns.

 

Thanks for the help Blnewt, I'll post up once i get it all setup

 

Hmmm...what would work better for my AWD sedan...19x9.5 +22 or 19x9.5 +30...w/ 245/40/18's???? Would either look good? Not sure...still try to do wheel homework