Unfortunately most of us don't have the spare dollars (or permission from significant other) to spend a bunch of cash on many mods at the same time. That leaves us with doing a bit at a time. Given the bit at a time approach, if you had a Calais V V8 with single spinner diff to start with, what order would you do the modifications in?

in no particular order, some options are.

cat back
diff (TruTrack)
OTR / Tune
breaks
extractors / cats
speakers
etc

??