Alclad makes a really nice Smoke shade, too. Tamiya's seems to be warmer/browner, and Alclad's cooler/bluer.
My exhaust technique depends on the plane. I'll usually use Smoke of one form or another as a base, then go over with pigments, slowly building it up with a small brush. I'm a big fan of Mig's Burnt Metal Blue. Adds a nice touch to the whole affair.
On my recently completed Spitfire, I went with grayer tones to match the references I had, and used an Aqualon Wisp brush to do the vertical streaking:
On the Bench: 1/32 Trumpeter P-47 | 1/32 Hasegawa Bf 109G | 1/144 Eduard MiG-21MF x2
On Deck: 1/350 HMS Dreadnought
Blog/Completed Builds: doogsmodels.com