The only thing I will caution about with add-ons, feeware or payware, is make sure they do not change or completely replace any of the default textures or default FSX scenery files
Anything that installes to the Addon Scenery folder, Sim Objects, or other areas that write their own files and folders is fine.
Anything that may change or overwrite default autogen, scenery, textures or coded defintions thereof may cause a corrupt or failed SP1 installation.
Any texture or autogen hacks as posted in the FAQ area of this forum must be REVERSED -or- a complete uninstall/reinstall of FSX must happen before installing the SP1 update.
FSX.cfg file edits will not be a problem however after SP1 you will most likely find you can EITHER raise frame lock OR raise a slider here and there, one of the two. The more powerful systems will probably be able to do a bit of both.
On a side note, I tried the replacement taxiway textures posted here. The add-on although it has potential and makes things look different, was not designed correctly and the detail1.bmp is not correctly sized or mip-mapped. It creates other problems one may not notice right away while looking at the pretty cracked concrete it produces.
Be aware that some add-ons although they may look pretty are not correctly designed.
I did not wish to go off topic here but I do want people to understand that some add-ons, like replacement taxiway textures and trees, as posted in the files area on this site must be uninstalled before applying the FSX SP1 update so I hope eveyone saves and backs up copies of these files before installing add-ons.
Any addon scenery that gets registered to the scenery library and has its own destination folders and files, will be fine and can remain
