Not sure about the "Impulse" per say, but I know for a fact that Millenium chassis have been raced around here with some awesome HP. From flathead stocks, limited's, opens, animal's, animal limiteds, to animal opens. Great chassis.
Charlie Stoffa used to have a wankel powered Rempest that won many races. The Tapmans in VA have a Tempest they use with big 2 cycles and Billy has won many races on it too. I race UAS on my 06 Tempest too and if yiublook at the roll of the UAS Nationals there were several drivers on them. I think Yow has raced a Vector in UAS too some time ago.