intranasal has a ~54% BA, compared to sublingual where it can range from just roughly ~20-40%(I'm pretty sure.. its something like, and average of ~32% sublingual). Plugging is much better than both sublingual and sniffing ime with suboxone and subutex.. plugging is hands down, the best all-around ROA for bupe.. I believe it is said to have a BA a bit higher than sniffing, but feels even stronger.. I slam my bupe pills now, witch obviously has the best BA, but its definitely the worst ROA as far as HR is concerned.. not good for you by any means, but I started doing it that way a couple years ago, maybe even like 3 years... and cant stop.. its also the most addicting ROA, one for the needle addiction, and two for the rapid, immediate onset.. Plugging, IME, hits you almost as quick as IV if done right, and is totally harmless as far as I know! But yes, even though its not advised to take bupe intranasal, it does work.. still, you would be much better off plugging it, for the higher BA and better feeling it brings.. can be a time consuming process, much like IVing can be, but the payoff is worth it... sniffing is nice, once in a while, when your in a jam and don't have much time to prep anything up or let it dissolve under your tongue long enough... that's the quickest way to do it, just like you would any other pill.. its really not good on your nose though..