I can only say that the Streetfighter bonus "Heating Up" is pretty insane. Not only will you attack very fast, but your Sneak Attack dmg will also be enhanced a lot. And that's not including the additional bonus you get when becoming bloodied.
If you like dmg output then this will be a lot of fun. A Black Jacket can switch around weapons with no penalty. So it's easy to trigger "Heating Up" with a blunderbuss should nobody flank you in melee. Also note that with a blunderbuss you usually have 4 projectiles that trigger on hit-effects 4 times - see Confounding Blind.
But... if you decide for blunderbusses (I mean that's not set in stone given that you're a Black Jacket) I would highly, highly recommend using Serafen's Hand Mortar and do his quest asap to get the second mortar of his - which is named "Fire in the Hole". Both mortars deal AoE dmg. Stuff like Blinding Strike, Crippling Strike, Toxic Strike and so on will get applied over the whole area of effect! As bonus those weapons are foe-only, have two damage types (pierce/slash) and target reflex with their AoE which can be a plus when meeting enemies with high deflection. AND Fire in the Hole has an enchantment that lets the whole AoE jump one time (like Driving Flight). And they are still "official" blunderbusses which can trigger "Heating Up" with the Powder Burn modal (which has friendly fire sadly, but it's rather weak). Best weapon set for Streetfighter there is in my opinion.
You can totally do Disciplined Strikes + Vigorous Defense, deal a AoE Blinding Shot into the crowd with the mortars, then close in with stilettos - since you are already heated up and the enemies will suffer big debuffs from the blind you will be nigh untouchable and mop the floor with them, stabbing left and right with great speed.
Sounds fun to me.