Without knowing a lot more about it, I'd guess he's got a pretty sizeable turbo on there. Probably of the GT30 variety?
Fairly sizeable turbo on a fairly small capacity engine does tend to be a bit abrupt in its power delivery/torque curve. Overly big intercoolers and plumbing exacerbate the problem.
Lots of people often build turbo engines with turbos that are bigger than they need. Similar with intercoolers.
But when you look at how car manufacturers do it, you see they use much smaller turbos and make them work hard(!). The Giulia Quadrifoglio swallows over 20psi to make its power and the turbos are far from big.
Personally, as hinted at before, I'd rather a smaller (modern turbo), make it work hard for the power I want. I'd sacrifice 20-50hp of outright power for a broader tprque curve and a more predictable engine.
Much like cylinder head ports, bigger aint necessarily better.