I had a chance to compare the Toyo RR (235/40/17) against the Toyo R888R (245/40/17) tires. As you can see the RRs are slightly faster than the R888Rs. To be fair though, I tested the R888Rs on warmer conditions (same day). I also have to note, since it was going to be even warmer after the lunch break, I decided to try the R888Rs before the track got too hot and skew the test results . I think I could've done a bit better with RRs if I didn't spend time comparing the two.

Toyo RR best lap time: '1':'59'.8'
Toyo R888R best lap time: '2':'01'.2

I had a chance to improve my PB by a full second on a much warmer day (around low 80s vs mid 60s last time). I feel that there is still some room for improvement on both tires especially on a better day (1-2 seconds maybe)

Both tires felt much better than the RE71Rs, even though I tested them on warmer day. They were both predictable throughout the session whereas the RE71Rs start feel greasy after a couple hot laps. R888Rs were a bit loose compared to RRs and RR has shorter gear and weight advantage which makes a noticeable difference on this track configuration. 

Mods:
Stoptech C43 BBK
Raybestos ST43 pads
OpenFlash Header and OpenFlash tablet 
Karcepts Sway Bars
Ohlins RT coilovers (11k/5k)
245/40/17 Toyo R888R tires 
235/40/17 Toyo RR tires
17x9" 6UL wheels (for both setup)