You're right of course. Even a Multiair can put out 170bhp in standard trim, which is the main tuning benefit of a turbo engine. What does worry me though is the difference between an engine modified for the street as opposed to one that is being professionally prepared for racing.
The Chevette I mentioned earlier was well known for having an almost bulletproof bottom end, having been earlier intended as part of a V8, so the pistons, con-rods and crank were well up to almost 250 horses. My next step would have been new pistons.
The top of the range Mitsubishi Evo needs a service every 4,500 - 6,000 miles as opposed to 12,000 for most cars which tends to hint at problems with that level of power. You have to question how long an engine would last if it's pumped up too far.