Chris

The tail cone is normal rather like full size F15 they get hot and discolor.
Ask away, many will usually read and not bother to post here. Some may have given up and your success will make them solve their running problems. On the first run up I would imagine that your JJ never went to 160000 as the pump needed more voltage to turn faster. After reaching 45k any JJ will run up to and even way past a safe 160k if given enough fuel[&:][&:], only to stop when temp or the bearings give up life[:@][:@] There is a good safety margin above 160k but you need to hit 160k any time the stick is at max. Reset up your TX and FADEC, to be sure you have no sub trim or reduced ATV on throttle before you start up.

Paul
RCdriver