you might need:
new clip-in bands for the inside of the front mech £free from a bike shop – £4ish?
new front mech – around £20 upwards.
new seatpost – £14 upwards (seatclamp comes with the titus)
bottom bracket – nothing new needed if you run a ht2 style unit at the moment.you might need to remove spacers if you run a 68mm bb,not add them.
the forks will fit as they are or possibly need cut down as thr titus xs headtube is short.
the rear brake hose might need trimmed down as it could be too long.
The xs motolite has one of the lowest stand-overs out there for 5″ travel.