I could, post install, just migrate the stuff to my standard FSX install. Fact is, I still need FSX:SE, which I do not have...
Theoretically, though I've tried to do this with a different product and not yet succeeded. Hopefully I've just missed copying something, but possibly there is a code check in there somewhere.
Note I've done a LOT of moving stuff between P3D, FSX and FSX-SE so I'm not totally clueless...
Also note you don't get to install something with Steam, it just does it for you automatically.
Which is usually for the good.
FSX-SE is regularly availably at 70% discount so literally just a few quid - good, but indicative of Dovetail's cost model - a loss leader to sell a bucket-load of DLC.
And FSX-SE IS better than FSX.
Cheers
Keith