Hi.
We haven't released such thing as "Seattle City X DEMO". We have only released "Seattle X DEMO" and this Demo includes both - the city and the airports. You may try installing it like this:
...but due to the mesh files and exclude zones installed too, it might be impossible to use both together.
Please note that many users reported FPS increase when using our Seattle City vs the default scenery so you might actually give the full version a try. If it doesn't work for you, you can always ask for a refund.
By using the wrongly called "Seattle City Downtown", I'm pretty sure that your version is much more efficient than the default one. Maybe, I will give a try in the next sale.. (Our currency is so much devaluated and we have a heavy tax load on foreign purchases)..
We've never performed such compatibility tests and we are currently not working on this product. I'm afraid it's unlikely that there will be a new version under p3d. But on the other hand I heard that they are working together pretty fine. Maybe you need to adjust the layering
I bought and paid for the P3D Seattle X from Flightsim.com and when I go to download it, I get a 404 error screen. I've tried contacting them but I was wondering if you could help me out?