6.4k does not need FAR or RF so you are good on that. However people might play with FAR on 6.4K so to have an option for those guys that do would be welcomed As for the reentry, I can say for the most part the vehicle can survive, there are two problems that still linger, one is that front landing gear hasn't got the buffed up heating so it explodes at about 100,000m, but that can fixed pretty fast. The other problem is that the cargo bay doesn't shield the cargo on reentry, causing payload and docking adapters to explode because of overheating. I have three reason why that might be, could be a improper number somewhere that allows heat to pass through, it might be because KSP doesn't see the shuttle as explicit as a cargo hold, over it could be the heating system in KSP in general (though I have Real Heat). Funnily enough those explosions caused Columbia to land in the Gulf of Mexico, though she survived a nice watery landing, yep she ain't coming back. (Pls put the picture above on the FP... need some humor there) I will post this on the official bug tracking for the mod.