If an aftermarket exhaust is used (Bursch) will a pair of exchangers from a 1.7 / 1.8 fit a 2.0? If not what's the difference?

I think you will get a better answer than mine, but I'll start. I think all heat exchangers will bolt to all engines. What must match is muffler to heat exchanger, ie, use a muffler for a 1.8 with 1.8 heat exchangers.

I think they all interchange pretty good, the big difference is the angle of the flange that hooks up to the head. Check the archives.

I have 1.7 SS exchangers and a bursch exhaust and its just grand (and loud)

Drew - it that mated to a 2.0 engine or a 1.7?

sorry...1.7 but I am pretty sure it doesn't matter. Here's a similar thread from last week.

Check the PP link to Bursch mufflers. Four different mufflers depending on which heat exchangers you are attaching it to.

Bursch mufflers

there are a few different systems and they all work. but i would get headers.

The main difference between the 1.7/1.8 HE and the early 2.0L HE is that the 1.7/1.8 pipes bend upwards and the 2.0 HE the pipes do not have the upwards bend. Both will fit on any engine but you need to swap everything as a package (HE, Exhaust Hanger, Muffler). A muffler from a 1.7/1.8 will not fit the 2.0 HE's and vice versa.