by the sounds of things, you just want to do it as a personal project so go for it!
I don't see the point though as it seems like a lot of work and money for only 137bhp. a mk2 16v will be just as quick and ABF's are 150 before you start modding. but if your addiment...i salute you
Is the aex exhaust manifold tubular steel or cast? welding cast is a dodgy business and I'd be surprized if it will stand up to the heat, weight and vibration very long.
What turbo would you use? the only small engined turbo I can think of is a glanza.
What injectors do they use?
Do you plan on using the standard ECU?
You will need a MAP sensor to get it to run any way smooth and at very least a Wideband Lambda kit so you dont melt the yoke! I just bought a Tech Edge one, hurt me at €300 so that would blow your budget.
I really think your mad to think about turbo charging an engine with 194k on it, pick up a low miler and you can fit the turbo etc to it in the garage before you rip up the car.