I contacted them about these and they guarantee they fit or send them back is what they told me and as for the TTI's I put a set on a Duster few years ago and had to put a few dings in them to get proper clearance but never tried Dougs
Ive saw the other discussions but was offered a good deal on the summit ones...ive got a set of 340 manifolds but not willing to pay the price for the head pipes to use them and none of the exhaust guys around here will try it