INARA has probably the best and most comprehensive Engineer section I have found for the game to date.
Check out this link and just go to the Farseer section, find the upgrade you want to do and make note of the required materials.
http://inara.cz/galaxy-engineers
You will of course want to be upgrading a 5A FSD drive for the Asp X, which is the max module allowed on that ship. Do youself a favor if you can afford it, and buy one or two extra 5As, store them at the source and then ship them to Farseer base via her Outfitting section. Then you can keep your better upgrades, swap in a fresh module and keep rolling without worrying about losing a previous high roll.
If you own other ships that also use the 5A, you can use any extra high quality upgrades for use in those ships. I did this with the 6A for my Anaconda, Python and Corvette. Saved me a lot of jumping by just using the Anaconda to get there and back with the 6As.

You can do the same with the upgraded Asp X with the 5A.