Not so much improve the bike overall but things I need to do to make sure I don't get into trouble out riding the trails Like what swazi_matt mentioned. Over time issue arise I'm just trying get on top of them before it's to late.
Hello from Norway, and welcome!
I am very happy with my 15 model. It's a 200, but apart from that I guess they are pretty much the same bike. Here are some points that I have done to mine, many of them to avoid destroying expensive parts:
*As I am old and slow, I have revalved the fork to get it softer / plusher. The Reiger rear shock is very good as it is, so I have never revalved that, just serviced it a couple of times.
*I have put on a Lectron carb, mostly because I had it from my previous bike and am very fond of it.
*I use T-Lock (a Swedish competitor to Tubliss) to get tubeless wheels. Very nice, as you save some rotating mass compared to mousse. I usually run low pressure, 5 - 10 psi.
*Bulletproof design radiator braces. I need them from time to time. Last weekend I crashed and even bent the brace a little. Can't say how damaged the radiator would have been without a brace, most likely I would have had to replace it.
*I have removed all switches from the handlebar, and run only a stop switch that is integrated in the brake pump clamp. I tend to wreck my switches nd they are expensive. I have placed the map switch on a radiator hose, as some bikes have from the factory. Mine was originally placed on the handlebar.
*I have also removed (or rather not replaced the completely destroyed) tail light. Gets destroyed sooner or later.
*Short Jitsie levers.
*Aluminium handguards.
*Last winter I bought an Enduro-Tech headlight. Expensive, but very good. I use it only during winter, during summer I run the OEM lamp (as it isn't dark outside when I ride).
*TM Design chain slider and chain guard. Lasts a lot longer than OEM, but are also more expensive.
I think you will be very happy with your 15 model. Mine has run approx 115 hours now and sure shows signs of being used, but no problems so far.