What is needed to change a set of wheels? + advice RE the cassette size I've found a set of wheels I would like to put on my bike and have a couple of questions about how easy it is to DIY the job &amp; compatibility. I have a 2010 Allez Sport Triple and want to swap the stock wheels for some Fulcrum 1 Clinchers. 

Principally my question regards the rear cassette - on the bike it is a stock Shimano 9 sp (from the Sora range I think). Will I need to change to a 10/11 speed for the new wheels? Will this require changing any other components or can it be just the cassette? **

** Note: This is something I'm considering anyway (probably Shimano 105/Ultegra [one can dream of top-level parts but there is a constraining factor called money in the real world], including a complete overhaul of all components inc. levers, cranks, dérailleurs etc.) because the Sora equipment leaves quite something to be desired and it is now quite worn.

Also grateful for any tips about knowledge or tools necessary for the job and other useful tips to be aware of.
Those wheels come either with a Campagonolo compatible freehub; or a Shimano/SRAM compatible freehub.

If you buy the one for Shimano/SRAM (as of this writing, out of stock in Wiggle), you'll be able to use your existing cassette. To quote @PeteH:


  "The 9-speed Shimano cassette that you already have, the total height
  of it is the same as the total heights of their their 10- and 11-speed
  cassettes. So any of them will fit onto a wheel, provided as @yivi
  says you have the correct freehub. Therefore you're not obliged to
  change from 9-speed."


Otherwise, you'd need to switch to a Campagnolo 10/11 cassette, and presumably change a few more things in your drivetrain for compatibility sake. You can mix and match (compatible) SRAM and Shimano components, but I think that for the most part Campagnolo is not compatible with them.  

You do need to have the proper tools to do it though. A cassette lockring tool and a chainwhip 




Then, it's as easy as this: