A ZXRS does kind of exist! I built one using the best parts of the ZXR and the ZXS.
It's quite different from this now as i refined the concept further with wider rear wing, teamline hubs, losi shocks, lowered CoG rear wing mount and more titanium. I'm actually quicker with this car than my TRF501X.. It's a very forgiving car to drive and light enough to be quick.