I spent some time on this issue this morning. I copied the contents of the zip to a folder, containing four sub folders. The names of the folders are a little confusing. One is called "no smoking barrels, and two are called "no smoke barrels or chimneys" and "no smoke barrels or chimneys (2)".
I went to Summit and set up for testing. All sliders maxxed, except detail radius set to small, autogen off, clear weather and traffic off. I used "Bob" for the vehicle. After doing all this, it occurs to me that the numbers are relative. Each person will have different setups, machines, etc. I even have different results at different times. I started by unloading the station completely and recording the FPS. I left the "Bob" vehicle sitting where it loads at, and faced the Headquarters building. I stayed in that position for each test.
The results were:
Unloaded - 9.0
No barrels/chimneys - 10.5
No smoking barrels - 8.6
No smoking chimneys - 10.8
Original configuration - 9.5
These numbers are inconclusive however, as turning my view to the left or right in any of the tests would raise the fps, regardless of whether or not smoke was in view. The view looking up the glacier produces 20 or more fps. When facing the HQ, the frame rates are lowest (even when Summit is not loaded) I walked forward and placed myself behind the HQ building. Now with the Summit station behind me (fps still 9.0), I turn around to face the station and uphill glacier. The frames are now near 20 with the station in view and all effects active. What I'm trying to say is . . . I'm not sure the ice stations are even to blame. I got higher frame rates with the station loaded than not, and low frames in one direction only, even with the station unloaded.
Low frame rates are a part of FSX that I have come to accept as standard over the years. It's the driving force behind system upgrades. I don't consider it something to complain about. I stopped checking my fps rates a while ago. The system lags are more likely as a result of missing objects or textures that the computer is dealing with, not ones that are working. (like the smoke, barrels, etc.)
All we can do is make sure we have all the object libraries, textures, and effects that are needed, and defrag regularly. Make sure you have plenty of free space on your HD for pagefile operation. And minimize background services.