If a GN and a WE4 were similarly optioned and made exactly the same HP, the WE4 would be quicker/faster by 3 butterfly sneezes as it has aluminum wheels, aluminum bumper reinforcements, and lighter trim.
Those differences amount to a few pounds, not hundreds of pounds as some have said.
When these cars were bone stock their performance varied all over the map. As such, one would not want to bet his hard earned money that any given WE4 would be quicker/faster than any given GN.
Since so many of these cars have been modified from stock over the years, the point is moot.
In essence, the WE-4 is a GN/Turbo T hybrid, closer to the latter than the former, much rarer than the GN, but worth less. Nonetheless, the WE4 is, IMO, a very interesting wrinkle on the usual, and certainly a very desireable car to own.