Borla has 4 headers for Vipers, 3 are street / race and 1 GTS-R racecar set. Do you know which model you're looking at, 17078, 17112, 17113, etc? That makes a difference. For a Gen 2 engine, the 17113's seem to be the best (1&5/8" primaries with 3" collectors). Though the peak # on a dyno graph may not be as high (approximately 7 HP short of an SVSi or Balenger header), the average HP of a dyno pull is pretty close as the smaller primary tube size works a little better on the lower (under 4,000 RPM) end.
I have the 17112's on the '94 RT/10 and the 17113's on the '96 GTS and am very stisfied with both. Hope that helps.
