Don't know much about this particular camera, but a lot of times, the "prime" lens ie the 20mm, often costs more than its "zoom" equivalent as they are normally a sharper lens (better quality pictures).
If you're looking at spending 1k on a camera I'd be buying from London camera exchange or Jessops where you'll get sales staff who know about photography.then ask them what they recommend for the type of photos you'll be wanting to take.
Have a look at Canon's equivalent and Samsung also.
The 20mm is an f1.7 which lets in twice the light of the alternative f3.5. Primes in general, especially anything going sub f2.8 are very expensive. On that crop sensor its going to be equivalent to a 40mm so its still a very wide lens so consider carefully whether its going to suit your intended purpose. Its wider than "human View" which is 50mm so in laymans terms, if your trackside at silverstone and take an image, the car on the image is going to look smaller in the image than it did to your eye.