As no one has replied I'll chip in
1st off I know nothing about RB kits
Other than they come in different capacities - suggest you give some more details of your setup here to receive advise from someone best placed
However, that said, there is some suggested gear ratio's on AF's gear chart here (link below)
CST4 isn't mentioned so you'd need to translate a CST4 to one of the listed exhausts
4.46 is no where close to the suggested ratios, so I'd have alarm bells ringing 4.46 is appropriate
https://www.afrayspeed.co.uk/media/other/53342287/45-tooth-gear-chart1..pdf