Mean looking? I dunno what you might want, but comfort and ease of handling are more important to me than what shivers my bike may or may not send up and down someone else's spine. I can't even really appreciate what it looks like while I'm riding.

Nothing screams "mean" like sky high apehangers, or 6" dogbones. Both of which have been used at varying times on one or the other of my Savages. The daily rider uses 2 inch or so dogbones in the stock base units, with a low and wide FL touring handlebar. F*** mean, that one was built to replicate a 50s vibe... lifted seat, wide bar, functional crash bar, floorboards, small windscreen, full rear fender, nicer taillight and rear signals... The Savage/S40, stone stock, is a cartoon, a nice cartoon, but still a 1973 saki induced knock off of a vintage English racing single, with bad brakes and a horrible electrical system.

Play on the bike's built in vintage vibe. Emphasize the engine. Swap to a real (side mount 7 inch diameter lens) headlight. Deep six the bloated rear section that looks like a Harley Super Glide bred a Honda Z50 "monkey bike" and had a love child.

You want it "mean"... Dirt tracker (look up Matchless G50 or similar). Street tracker (study the late great Norton Manx). Rigid chopper/bobber (Voodoo Vintage or Ryca based is easiest).

Heck, just look at some of the rolling abortions I've built out of my 98 over the last few years... I managed to literally melt most of the electrical system. Looked alright, ran like crap, handled great and always drew a crowd.  

I flat wore this bike out. Most "popular" build scheme it ever had... ... it gave up a bunch of parts to build "Sam",  my daily rider...
... a 2003 with an SS Death's Head on the rear fender... that little black 50s style build scares a lot of folks...

Versy's beast has some pretty mean looking bars.