RE: TNX 5.2R, REVO 3.3 OR MGT 4.60
The TNX comes with a .32 (5.2), most tracks only allow up to a .28 (4.6) So yes.. unless your track doesn't care, some don't... I'd call and find out 1st and then make your decision... Going with a .28 would mean you should be ok for all races though, wouldn't have to worry about calling ahead of time, to see if it's allowed..