Really hope it is classified as a vintage as I have just bought one to go vintage racing at Hinckley!
I remember going to the Worlds in '93 in Basildon, where the XX first appeared. It was a big thing, as it was the first moulded tub chassis. Here it shows it was released in '93.
http://www.rc10talk.com/viewtopic.php?f=27&t=10417
Plus someone else on the same forum is racing his in the USA vintage Nationals.
I have deduced that it must have been released late '93 in the UK as I remember my brother and I getting our Cougar 2000s for Christmas '93, and the Losi was available then I am sure - cos at the same time everyone else switched from their 2000s to XX's which were always quick out the of the box.
Hinckley's cut off for vintage is '93, and they do allow Cougar 2000s! However, if we turn up and they say 'no', I should be OK as we have a spare Cougar 2, Topcat, Procat, Ultima, RC10, Meteor and brace of Apaches - just in case!
Fingers crossed, eh!