First off (may not be FSUIPC related), I have a chproducts USB ProThrottle so I am trying to map the throttle on my joystick to the spoilers.  When I do, the spoilers are bouncing up and down then finally settling down at full, even though I only want say 1/4 spoilers.  I can't find anything interfering with it and when the joystick is mapped to flaps or throttle, everything is fine.  Any ideas on this?  I do have the registered version and have tried the joystick control to set the range but to no affect. 
Second, anytime I run a weather program (either FSMeteo or AS2004), after about 10 seconds of setting the weather my system drops down by 10 FPS or more.  Then every second I get a hesitation, even at cruise altitude.  Yet, when I use the built in weather download, I may lose a max of 2 fps in really bad weather conditions. 
I have the latest version of FSUIPC, a fresh install of winxp and fs2004 with no other addons installed.  To give you an idea how much I lose, if I run the barebones FS2004, ie NO addons, with all settings to max, I can get around 48FPS on average at KSEA with the default 737. 
Then I add FSUIPC, and fire up either the FSMETEO or AS2004 and I am down around 15 fps in 2d panel mode and I get around 18 in the VC or spot views; and thats with turning AI, autogen and display sliders off/down.  I've even limited cloud layers in AS2004 to 2 layers. 
I do not have a slouch of a system either.  A P4 3 Ghz, 1 Gig ram, ATI 9700Pro 128Meg card blah blah blah. 
I think there may be a problem somewhere as it appears weather is being pushed into FS on a regular bases, instead of just when the external weather program is scheduled to push it in, but just my own observation. 
best regards 
Fraser