I started my build on the 25th of November 2011 and it was registered at the end of May 2012. It was ready for the IVA mid April 2012 though. Total build time in the region of 285 hours. (and I really enjoyed it).
I went for the full kit. The Kit covered all you really need though a little bit of upgraditus did creep in almost immediately. Though it is easier to make sure changes during the build rather than afterwards. I also sent my back to the factory to have the Geo and Engine setup correctly and for a pre-iva inspection (circa £600)
The cost of tools really depends upon what you already have, I was lucky I had quite a few of the basics (good socket set, spanner set, compressor, power drills etc) but there were more required. Most were sourced off ebay at a reasonable cost, probably a few hundred pounds in total.
I have a double garage but the Westi lived on one side though I did use both at times.
For me building the car was part of the desire behind it.
I also have a build blog http://rhetts-westfield.blogspot.co.uk