It's an interesting one this, if you look at the photos of the bottom ends between both a 182 and a 197 engine you can clearly see that they run a different setup with regards to the alternator/water pump/power steering.
The 197 block looks Identical to the megane 225 F4RT block, however if you look at pics of the cylinderhead it looks as though it shares the same head as a 182 (with different size ports) as it has the same breather blanking plate.
We all know that the 182 runs a jc5 gearbox, but the 197 runs a 6 speed tl4 gearbox.
Now there are a couple of unknowns, the jc5 and tl4 have never been measured side by side so it's difficult to say if it will fit in the bay, on the flip side though if it's a case that the bottom ends are identical between the 197 and 225 then why not just fit the megane engine in? if the tl4 box is shorter then you could possibly use that instead of the large ND0 box found on the meganes. You'd probably have to get custom drive shafts though.