Varex Switchable exhaust system

Does anybody have any experience with switchable exhaust systems on exiges? I currently have a stage 1 on my '07 Exige S and love the idea of getting something a bit larier but still want to be able to do the odd track day / motorway run (it’s my daily driver).

Someone with a supercharged elise has installed a Varex system and it sounds great Lotus Elise Varex silencer - YouTube

Theyre pretty cheap (<£300) I’m tempted to give one a go along with a decat. Is there a reason why more people havent done it such as MIL caused by changes in exhaust flow? I used to have an M135i and BCS Powervalve exhausts (same idea but controlled by boost rather than a remote) were quite popular.

http://www.xforce.com.au/products/varex-mufflers

Cheers,
Dan

That still sounds pretty loud on standard mode you might have issues with noise.
Also will the standard mapping cope with the change in flow??