Hello and welcome to the 626 community!
Since you're refering to KM's and LX trim level I'm asuming you're either Canadian or an European. I'm going to guess Canadian due to the fact that you've said you got the mid-trim model, as there is only 2 different trim levels in Europe (AFAIK) And the LX would in that case be the mid-trim (Or so I believe)
There is not alot of thing to upgrade performance vise, but our 626 guru DjDevon3 has ALOT of useful videos and how-to's when it comes to maintenance and repairs, you should check out his youtube channel here: https://www.youtube.com/user/DJDevon3
As for exterior/interior upgrades there is a few aftermarked things to do. But it all depends on what you are looking for. Something easy to start with is for example LED bulbs all around.
Hope you'll enjoy your stay!