I also have the same problem with the tail pipe. I noticed from another thread on RCU that someone had cut the intakes right back which puts the turbine more on the c of g.This then means you have to cut a notch out of both sides if the turbine mount to fit around the ply former which is in the way.(Sounds drastic i know but i checked this out with Ali Machinchy and he confirmed all this was ok to do.Ive also been told the correct distance between the end of the tail cone to the tail pipe (excluding the bellmouth) is 40mm (1.5 inches to you american guys)
Hope this is of some help.
Rich