Lambda sensors - HELP!

Hello everyone.  I have a Suzuki VL800 2005 model and I'm based in the UK.  I'm about to upgrade my exhaust to a Cobra Streetrod Slashdown.  Looking to order from Custom Cruisers.  The website says that models up to 2006 only need one sensor installed whilst models from 2007 onwards need two.  Despite this, I've heard conflicting views on other sites so I was wondering if you guys could advise me whether or not I need to order this exhaust with one or two sensors fitted.  Also, I'd love to hear everyone's opinion of this exhaust too before I make the purchase!  Cheers, Jess.

Hiya Jess.
Mine is a 2006 and has one sensor.
I would imagine the exhaust is loud, so you may need a friendly MOT guy.