PeanutButterOrifice-
I was bored and learned as much as the interwebs allowed on the xb-e. This is the best place for knowledge, and is still somewhat limited:
http://www.redcatrampageforum.com/
Here are the 5b wheel adapters:
http://www.rampagehopups.com/product.sc?productId=672
The adapters are $80 but seem to be worth it in opening up tire selection. Even with an off brand redcat stepping up to 5th scale does mean stepping up spending.
The MMM/1717 combo are the hot ticket. There are 2 guys on the above forum coming forth with aftermarket parts for weak points. Stock parts are easily available from redcatracing.com. All in all I see no reason not to purchase this car.
I wish I had known before I took the e5b plunge. I could have had 2 or 3 of these. Oh well.