That's not the usual welcome we give new members to Simviation.
I didn't check his number of entries, I should have welcomed him, that's right, my mistake
If that's the best you can do then don't waste your time answering. The main purpose of this forum is to help & encourage people.

The best I can do, when I register to a new forum, is to read it first before asking questions.
Welcome to the forum lowflyer. The best answer I can give you is to try it. There's too many variables now to give specific advice. You might need to re-alias panel & sound to an FSX default aircraft. It will either be compatible with FSX or it won't.
Yes, Welcome to the forum lowflyer, and sorry for my initial -quite impolite- answer.
You have to know that your question has been asked hundreds of times already. A summary:
- A lot of recent FS9 planes will work
- A lot of gauges are no more compatible, so a lot of panels of FS9 planes will have missing gauges
- if you know how to edit a panel, then you can change the gauges to replace them by compatible ones, but this might be difficult on the planes like liners, because they usually have A LOT of gauges.
- more and more FS9 freeware planes are being updated and reuploaded in the FSX section with corrected effects, gauges, panels etc... Check the FSX download sections
- with the newest support package, nammed SP2, some textures format are no more supported, so a lot of planes and gauges are getting problems. This SP2 however is only included into the payware package called Acceleration. The SP2 will be release as an independent freeware download later this year. Until then, you'll have the SP1 to download and install on a fresh FSX.