Not many places offer turbo 'kits'. Not in Europe anyway. You will need to make substantial
mods to the engine's internals to loewr the compression.
Different pistons and/or connecting rods. Personally I'd do both and lose the geometric compression in two places rather than just rods or just pistons which can really load up the side forces on the cylinder bores. It's very possible you'll need different camshafts as well to make the best of the installation. Cooling is worth attention. An oil/water heater exchanger (if not standard) is a good idea. Some turbo engines have little oil jets in the crankcase which squirt oil onto the bottom of the pistons to improve cooling. Sodium filled exhaust valves help to end heat dissipation as well. An intercooler is, in my opinion, also an essential with ANY turbocharged car.
Pipework, manifolds and exhaust system will need to be changed.
You'll need an ECU that can be coded to operate and manage the fuelling WRT the turbocharger(s)'s input of extra oxygen.
Let's not dismiss either the running gear, suspension, brakes and tyres.
Not a cheap option in my opinion, BUT, it will be a very special and totally unique car afterwards.
Alternatively, how about a Nissan 300ZX twin turbo?