Q: Can I use RamJet-X controllers in conjunction with a Carrera Ultimate race set that has two wireless controllers.
A: Yes, you can use a mix of wired and wireless controllers.
The Wireless+ receiver gets plugged into port 1 on the Control Unit
The RamJet-X controllers would connect to ports 3 and 4.
When binding the wireless controllers to the receiver, do not use IDs 5 & 6.
That's the part that can be confusing. The ports on the right of the Control Unit are labeled 3 and 4. When using only wired controllers, those ports use IDs 3 & 4. However, if a Wireless+ receiver, IR tower, or controller extension box is connected in left ports 1 or 2, the right ports then use IDs 5 & 6