Hi guys, and welcome.
I might be able to help as I recently modified my DRB in order to lower the floor underneath the seats to the same height as the footwell. I'm 6'6 and my field of vision is now in the top third of the screen whilst sitting comfortably.
Pics and descriptions can be found on my blog:
DRB rebuild blog
As you will see, I had the location on the cats changed so that they hug the gearbox and then into flanges, into a collector and then a single pipe under the tails haft.then into another collector, into mufflers on either side of the tank and finishing with hidden dumpy pipes.
I hope that this helps
