turboing a 1.6l
 

What differences will i face compared to a 1.8l? I heard if i'm going over 200 hp on a 1.6 i would need to change the diff, is it true?

You need to change the diff regardless of turbo or not. Those break at stock hp which is nothing on the 1.6.

Would it be possible to maybe use a BMW differential, which are much cheaper here than miata parts?

If you are willing to fabricate a mounting system, anything can be done.

Mounting is cheap/easy. Axles are not.

Where is "here"? That might help us. Sounds non-US to me. If that's the case, what year is your 1.6? Unless it's a 90-93, you already have the larger diff as far as I know.

Estonia, there is only 4 miatas for sale on the biggest site and theyre all mark 2s. I actually don't own a miata yet, but i will buy one from germany very soon. I'm just trying to think if extra 2-3k is worth for a 1.8l.

Get a 1.8. Other than that, cheap parts can be had from UK, if you find a way to transport them

94-up 1.8 got larger diffs, brakes, clutch, fuel tank, variable throttle position sensor, better heads, better chassis stiffness, better ignition coils, and a bunch of other differences.

Guess i will go for the 1.8l, thanks all for being so helpful!