I wanted a 16v, but, if ya intending on getting a Williams, I dont see the point.. by the time youve lost money on the 16v, and then bought a Williams, you might aswell have just bought a Williams in the first place.
The insurance can be an issue.. last year (I was 20) a Valver was pretty much 1/2 the price to insure! (A lot more people quoted me on a 16v than a Williams.. )