[barkeater]

I think the armor you get for your bike should depend on the type of terrain you ride.

If you ride lots of open, muddy terrain, I'd stay away from rad guards. If you ride in the tight woods, a rad guard will keep a small miscalculation or unseen branch from turining into a big mess. They won't keep you from pop-canning the rad, but will prevent a small whack or pointy stick from ending your day. ANY rad guard will collect mud and restrict your air flow - $100 or $25. Something to keep in mind.

Handguards are not optional for me up here in the Minnesota woods.
I also will not ride a bike without a Scotts damper - but it's a personal preference.

If you cross a lot of logs or rocks, a skid plate would be a good investment. I've seen lots of flat frame rails under the motor. If you don't encounter those types of obsticals, all they do is make it a pain to change oil and add extra weight to the bike.

Pipe guards are more for show than anything. If you hit any pipe hard enough, it will flatten - no matter how good or expensive the guard.

The impeller is a peace of mind thing. I have one after seeing what happens to the stock plastic impeller. I have also switched to waterless coolant.

You have to be prepaired for the type of terrain you will ride and your riding style and protect the bike accordingly. Again, if you ride a lot of fast, open terrain, you don't need much - if you bulldog new trail through tight brush or rocks, you'll want some armor.