Hey Fringe,
I don't have access to my car at the moment, but I thought I could help with measuring the Ti tips for you.
I took some quick measurements from the mounting hole on the tip to the backside of the tip, so you can get an idea of length.
Measurements are in MM.
Here is how the tip sits on the exhaust. Excuse my crude MS Paint skills, this is a very basic idea. But you can see how the exhaust tip extends past the steel inner exhaust, and also extends outward toward the rear of the car. Also, of course, the inner steel mounting piece has an oval mounting hole, so you can adjust the length. Pretty simple.
Here is a picture from the edge of the mounting hole to the edge of the backside of the tip (Not from the center of the mounting hole)
Here is another picture, where I tried to measure from the center of the mounting hole to the backside of the tip.
And here's a somewhat close measurement of the mounting hole to the EXIT of the exhaust tip. Don't forget that the tips are slant cut.
I hope that helps some. When I get my car back, I can do some more caliper measurements of the actual tail section of the exhaust for you.
EDIT: I also wanna note that from the side of the car, you could see the backside of the tips, showing that they were not a uniform piece of the exhaust. Not saying that it was a bad look, in fact, I loved the side profile, just a note I remembered.
I think an XVO Afterburner tip that was around the same length or somewhere close to the stock HKS tips would be good. Any other opinions on that?