Being that I'm historically a Vauxhall man and the way to cheap power in a small one is to use the engine out of a big one, I'm thinking about something Focus/Mondeo/whatever for my Puma.

Is this a viable change? I'm happy to undertake the work but just after some debate on what would make a smooth conversion which is an effective upgrade but not too expensive.

I'll probably source an entire car so the list of parts isn't the issue, just need to know what to look out for.