The reason people dont beleive you is because the 1.6 Focus produces 98bhp and has a top speed of 115mph... Sadly mate your filter and exahust at best will give it 5-10bhp more which is no where near enough to get to 140mph.

But that aside, to answer your question I also think it would be much easier and maybe even cheaper to just buy a 2.0 Focus than to retro fit the engine, ECU, etc..