Sweet! That’s a great bike. The geometry might be old school but I am sure it is more than capable offroad.
Here are some things I’d check or have checked:
-
You should check whether the shocks and the fork need servicing. Usually the rubber seals and the lubricants dry out.
-
Another thing is tires, check if they are new and need replacing. In case you need new ones, go tubeless.
-
Check the drive train. This is a high-spec bike, and in my experience that often means it has either been ridden a lot or very little. If it has seen a lot of use, you might need to replace some drive train components (inner and perhaps outer cables, etc.).
-
Check whether the brakes need to be bled and whether you need new brake pads. Feel the discs for a lip. If you have calipers check whether you are still within spec in terms of minimum thickness.
-
Check your BB: is it still running smoothly?
-
Check the pivots of the suspension. Grease them if necessary and then torque them to spec.
-
Check your headset bearing.
In case you don’t feel up for this, don’t worry, take the bike to a bike shop you trust and ask them to overhaul it. Maybe they will do things you deem not strictly necessary, but IMHO it’ll be worth it. Mountain bikes take much more of a beating than road bikes, and if you invest a little now could give you a bike that is still good for several years.
Now for upgrades: I’m assuming that all other components are in working order, and you just upgrade them because you want to. Clearly, if your drivetrain is worn out, you need a new one.
-
A dropper post. This is probably the biggest upgrade you can make.
-
Go for a 12-speed drivetrain. That’s probably pretty obvious. Probably you could get a 12-speed Eagle GX drive train and new front chain ring, and use it with your existing cranks. Alternatively, go for a 28-tooth chain ring in the front if you need lower gearing — 28:10 is still plenty fast offroad and 28:42 gives you roughly the same gearing as 32:50.
-
In case fork and damper need servicing, you might think of replacing those. Keep in mind that this is a high-end bike, so please don’t anger the Gods of cycling by slapping on cheap components.