http://www.lotustalk.com/forums/f25/mwr-elise-v330-3-5l-v6-330hp-na-elise-88287/ This is all posted by MWR but I couldn't get the images to show up under the quotes: Monkey Wrench Racing: We've been working on this one for a while, sorting out a very clean install requiring minimal...
Anything can fit and run with the right amount of money/experience.
Looks like you will also need to fabricate a new trunk lid as the stock one wont fit due to clearance, also have to do some trunk maintenance (make smaller) to fit the block. Give MWR a call or email and see if they can give you a build spec, but first I would ask them how much time and $$$ they dedicated to it, to see if its something you want to do.
Just buy an Exige V6 if you're based in Poland - Lotus did all the hard work, R&D, snagging for you. No aftermarket install will get even close.
Over in the UK, the early V6 S Exiges ( 2012 onwards) start from low GBP 30's k - Exige S2's have similar prices even though they'll older, so theres a cross over, as not everyone agrees the V6 is better. You could pick-up something really nice below GBP40k. Later cars such as Sport 350 / 380 / 410 / Cups cost more