The Nc3 and g4 line is aggressive against the Caro-Kann, but I find it to be much nicer to setter for the quieter advantage offered by the "positional" line w/ Nf3, Be2, and O-O which was championed by Nigel Short. 

In response to Sacanode's audacious Dragon comment, I would like to note that Black is fine in the 9. Bc4 Main Line (w/ Bd7 and Rc8) and it is primarily in the 9. Bc4 w/ Qa5 lines that Black is having problems (in addition to, at least according to John Federowicz, 9. O-O-O. Though I would personally disagree with that assessment).

Darn emoticons!  I meant  Rh8 and Kb8.  Apparently, "8" and ")" next to each other gives  8).  Annoying.

I am minded of the old joke:  A man goes into the doctor's surgery: "Doctor, doctor, it hurts when I raise my arm." The doctor replies "So don't raise your arm".  Not that funny, but it seems to me if you are having trouble with this line after analysing it so extensively, you should consider playing something else!!

Ha!  Go tell that to the Dragon analysts!

Actually I play the Dragon myself, but I'm thinking about adopting another Sicilian for exactly the same reasons in light of the many problems black has been having the 9.Bc4 Yugoslav.

Okay, that's not really related to this discussion (Hey the forum said 1.e4... right? ), but this reminded me of similar problems I have faced when trying to make risky lines work in home analysis.  It's frustrating to not be able to play an opening because of a problem line, when most of the lines people play (the inferior lines  ) suit your playing style well.  Some people just ignore the problem and hope their opponents are not aware!

Okay, I know that isn't any help.  I don't play these lines, but I looked at the analysis.  At the critical position at move 16, it seems like white is in big trouble if he doesn't do something drastic fast, since black has obvious targets on queenside that he can attack very quickly.  It seems like white needs to blow up the center somehow to make something of his position.  I couldn't find any other sacrifices on move 16 that looked very promising, so as far as I can see 16. Qg5 looks like the best active approach, as the other moves given seem too slow.  In the main line given, instead of 19.Qxb4, 19.Ncxd5 looks very tempting, especially considering that endgame looks very unappetizing with white's bad pawn structure. 

19. Ncxd4!? exd5

(19...Qxg4 I think white can hold his position after regaining the piece, but it's complicated.  Here's a same ple line in my analysis, illustrating a neat idea:  20. Nxf4+ Kc7  21.Nxh7 Rxg4  22. Rd7+! Kb6  23. Rxf7 Ne5  24. Rf6 and white maintains an initiative, a pawn up.)

20. Rxd5+ Kc8 and now I think 

21. c4(!) is the best way to maintain the attack.  At the moment, white is down two pieces down but it looks black is about is lose a piece and white already has three extra pawns.  From black's perspective, it seems difficult to find an active plan since white's king looks relatively safe, despite the opening of the king's position by c4.  Then again, for white to make something of his position, he like has move his queen from the protection of c4.  Also he is low on pieces.

After 21...Rh8 (trying to keep material), 
22. Rhd1 looks best, keeping the pressure and threatening Nxh7, regaining the piece.  Then 22...Kb8 looks like the only way to avoid the immediate loss of a piece.  Then 23. e6+ looks best and things look dangerous for black, though maybe he can survive.  I think white might have at least a draw here.

Here's the full line for clarity:
19. Ncxd4!? exd5 20. Rxd5+ Kc8 21. c4 Rh8 22. Rhd1 Kb8 23. e6+

After 23...Kc8 24. Nxh7 Rxh7 25. Qf5 looks good.  For example, 25...Qxc4+ 26.Kb1 Rh8 27. e7+ Kc7 28. Qd7+ Kb6 29. e8=Q.  And if 23...Kc8 doesn't work, I think white has at least a perpetual after 23...Ka7.

I hope this helps.  It's nice if a tactical line like this works against the Caro-Kann, since it's such a solid opening.

Uh, it looks like you're more of an expert on this than any of the rest of us.