That particular installation has plumbing that looks quite vulnerable to damage. Okay for a street bike, but if I wanted a street bike I would get a bigger engine. i expect this rider is limited by license regulations.
Most of the time, any significant change to intake, exhaust, or internal engine parts can be improved upon by rejetting. Does not matter the engine or modification.
Easiest way to plumb a turbo is carb-turbo-engine, but off-idle throttle response tends to be somewhat lazy. Accel actually built a valve that operated on pressure that bypassed the turbo until boost was sufficient, providing better throttle response. Worked pretty well. A turbo-carb-engine configuration provides better off-idle throttle response, but longer turbo lag as the turbo has more intake to pressurize. Plus, the carb needs to withstand pressure, making the current gravity-feed system unable to deliver fuel.
The easiest way to pressurize a carb is to put it in a box and use a fuel pump with a regulator to keep fuel pressure just slightly more than boost pressure for adequate flow. A box creates a HUGE intake volume that needs pressurization, resulting in intolerable turbo lag. The right way to pressurize a carb is to seal all the carb vents and shafts, and forget using the late model carb as it operates the slide with vacumn.
Adding an intercooler merely creates a huge intake volume that results in huge turbo lag. Cooler, denser intake charge can make more power, and tricks like pop-off valves and such can be used to keep impeller rpm up during coasting, but making time through corners often requires throttle and brake at the same time to avoid a huge bog exiting corners.
The best solution for throttle response is a combination of direct port fuel injection, minimum intake volume, and a small turbo that spins up fast. For max power, cooler intake charge, bigger turbo that flows more air. Like any other engine tuning, it's all compromises.
I'm wondering how this builder oils the turbo bearings. They need a high volume of cool oil to avoid siezure from exhaust heat literally cooking the oil. Oiling is super critical to turbo life. This problem is all that keeps me from a turbo TW.
Finally, for maximum performace, a very low static compression ratio and camshaft with minimum overlap and duration are desirable. Pressurized competition engines generally have static compression ratios of about 8:1 and cam timing typical of engines designed for maximum fuel efficiency, but with more lift.
I've thought about a turbo TW. I'd be looking for better speed-holding capability on the highway, but I'm not willing to sacrifice the stock off-idle torque and throttle response. I already have a homemade direct port EFI that can replace the carb on a TW. It's been running on a 21hp riding mower since early last summer without problems. It is sized to adapt to the stock '01+ intake manifold. Not to difficult with DIYEFI.org as a resource. EFI would allow rapid off-idle throttle response without the pressurization issues of a carb. I'd use a slightly oversize turbo so boost at low rpm would be insignicant. ~6 pounds of boost at highway speeds would increase power by about 50%, but there would be plenty of air flow to keep the engine cool. It would be a lower-cost and more fuel efficient option than a stroke and bore, but it would add some weight.