Well before I begin there are a few legal issues to explain about this, starting with the fact that if an exhaust states "not for road use" it's not strictly road legal, now as long as it doesn't strike the decibel levels that will get you pulled over it's fine day to day. However you will have to put the stock exhaust back on for MOT, mainly because they can point to the writing on the exhaust that says "not for road use" on it. Some people take to removing these embossings in various ways - A simpler solution would be to seek out an exhaust with a removable baffle, meaning it's road legal and you can just stick the baffle back in for MOT tests, rather than keep the old exhaust in the garage and change the whole thing every time.
As said the project's not a tricky one.
The hard bit is finding your exhaust, do your research and know what you want from it, the Remus pictured is a racing exhaust and has certain properties, it's notably lighter in comparison to the stock one, steel versus aluminium so it's not a big shock that it's lighter. It also tends to burble and crackle under normal engine braking and if you do it in a low enough gear on purpose it backfires, loudly. That's good for some and bad for others...
Anyway, Tools and such:
- Spanners, allen keys and a socket wrench, it'll vary bike to bike but those are the main things you'll need.
- Can of WD40 or a better penetrating oil
Note: Remember to let the exhaust cool down before attempting anything, it can get fairly toasty even after a short ride...