I have seen that site before. there are numerous sites selling Weber parts.
If you know what you want or need, call Weber. They will be cheaper.
And if you get in on the free shipping promotion, its even better.
There is currently one going on right now!
Free Shipping on weber.com between October 22, 2012 and November 26, 2012*
Just enter promo code GOURMETBBQ2012 at checkout.