Well Sir, I can't speak for the model year 2000 but, I can for the 2007 two wheel drive Grand. I'm not fan of either of the options of the pump or the drive shaft disconnect. But, that's beside the point. On our Grand, which was the Overland model and had the 5.7 Hemi in it, the drive shaft was 6.5" in diameter and it was/is aluminum. I spoke to a couple of Drive shaft disconnect installers none would even touch altering that drive shaft.
In hindsight, I'm really glad they gave me that answer because many of the folks who've had the D/S disconnect have had lots of problems with them. And, as for the pump, there's quite a few running around but, I just could not afford to take a chance on that pump in a $4,000 5E auto trans.
It's your car and you have the ability to choose what you want. Personally, if you really like the Grand, trade it for a four wheel drive model of the same year and outlay and be done with it. Those are flat towable right from the git go. Your choice. Good luck.
2004 ITASCA HORIZON 36GD, 2011 GMC Sierra 1500 4x4 Toad '08 GL 1800 Gold Wing
Retired-29.5 yrs, SDFD, Ham - KI6OND
Me, Karla and the Sophie character, (mini Schnauzer)