I am looking to have large races and would prefer equivalent car sizes and capabilities. It looks like Digi-q is the way to go, but I want more than 4 at a time. I saw that the Nikko iRacer size and performance appears to be on par with the Digi-q and has 5 IDs. I have no idea whether I can run any or all 4 Digi-q and 5 iRacer IR IDs without interference between them. Has anyone tested to see whether this is possible?