I have done pretty much what your saying although I started with a JWT LHD twin turbo kit from the states.
The only bits bits I was able to use was the turbos, intercooler basically. All the piping was custom, manifolds custom, fuel lines, exhaust, oil lines, coolant lines, fuel pump, bigger sump etc etc
its a lot & I mean a lot of work it took me 3months of 6hours a night on and off there is a reason why garages charge the Earth because the labour you put in will be ridiculous.
also on cost the little parts mount up it’s the jic fittings that surprise you the most ha
but if you do undertake it good luck and you will enjoy it in the end I’m now running 420bhp safely touch wood for the past 3years.