Tuning a rare kei-car? (Subaru Vivio)

Hi, I might be buying one of these in a couple of weeks, and would like to squish some more horsepower out of it.Now, this is quite the rare car (they were never sold in the US AFAIK, and there is only one for sale here in Norway). So performance parts aren't exactly of great availability.I would probably start with a cold air intake (the engine bay is tiny), and then an exhaust. The problem with it is; I can't find any exhausts made for this car. And I can't weld either (I'm no mechanic to say it like that). Is a custom-made system the only way out?Some info about the car: 1996 Subaru Vivio 660cc 44hp EN07 engine 680kg (1500 stupid freedom units)TL;DR: I want to squish extra horsepower out of a 44hp engine in a tiny, quite rare car. On a budget. What can I do? via /r/cars http://ift.tt/2tUEjss