Using cocaine while on suboxone can be dangerous as it can sometimes dull the effects of coke, and that will in most cases lead the user to believe they are fine to re-dose. (Until they aren't fine and overdose) as I have heard by alcohol drinkers, its very easy to drink a whole lot more than usual while on cocaine , similar kind of effect it seems. Thats only one of the risks. No one here can give you a concrete answer because there's simply too many variables, if you do really care about safety, then I would not go ahead with it. (Not to mention 2 years since your last stims)