Boost control solenoids can pack up giving little or no boost.

Other thing to look out for is cracked blocks giving misfire on hot start.

I have replaced an engine on an ST for this problem, not sure how common it is.
Would misfire then clear on hot start,removed plugs, one had signs of coolant contamination.. removed head cylinder 1 had a crack about 10mm deep in the top of the bore. New motor from Ford about £3k.

It's expensive kit, but the Mountune 260ps cars go very well IMO.