Hi Capttrob,
I'm guessing wiser heads than me will reply to you soon but....you're getting reasonable FPS for your rig.
I have a P4 3.2Ghz prescott (socket 478) with a GF6800 Ultra and 2Gb of ram and I get about the same frames as you....difficult to compare directly cos I fly the Su-25 or the 'T', which is much more of an FPS killer - even in the frog I get 25FPS online...or I did until my mobo died so I'm upgrading at the moment.
I did find there is a real balance between applying tweaks for FPS versus how the game is affected...let me try to clarify what I mean.
I did some 'visibility' testing in the Su-25T to see how close/far I could detect ground targets. At the initial test I had a few mods installed, including the FPS tweak "2.0". I could detect targets up to 15km away.
I then did a reinstall of LO and only installed mods such as teka's HUD mint mod, realistic sun/moon and stuff like that....no FPS related mods though.
I retesed visibility and now I can see ground targets up to 25km away...if I know where to look in the first place.
In other words, be careful what FPS tweaks you install, because its always a compromise between speed and quality. As a mud mover its really important to me to see ground targets and scenery as far away as possible....whereas as a fighter jock you won't need to care as much about that.
Anyways, to answer your question....you get reasonable frames already...there is no easy solution to 'stuttering' when flying through smoke...no CPU/GPU seems powerful enough and...if you do install an FPS tweak do some before and after testing to make sure you are getting some benefit at a reasonable 'cost' (i.e. not dramatically reduced visibility of 'xyz').
Again, some wiser minds may chip in here and offer some more productive advice.