The Willy is quicker than the VTS from A to B, but not necessarily much if at all in a straight line at legal speeds. The book times for the two show similar 0-60, but with the Willy opening a bigger gap by the ton (about mid to low 7s 0-60 for both and 20 for the Willy, 23 for the VTS IIRC). VTS in-gear figures are on the whole a bit less than the Willy.
There are some "freak" examples of both cars though: theres loads of footage on here of some VTS drivers giving Williams a serious run for their money - ask Craggy
Not all VTS are that fast though, just as not all Willys will do 0-100 in 18 secs or less like some.
As for a "real world" tussle, the reason a Willy would win IMO is because of its really fat torque spread. Out of T-junctions, roundabouts and so on would be where a Willy would open the gap.
Its like the difference between a Valver and a Willy really - if you race a Valver when its on-cam, then theres not a massive difference. Add a few obstacles, tight corners and so on and the Willy will show its teeth.