Do 2.0 headers fit a 1.7 and do you have to have the exchangers on the headers. I don't need a heater/hot air in my part of the country. Thanks Mike

You'll need a matching muffler.

The only difference between the 2.0 and the 1.7/1.8 is the tube diameter (1.7/1.8 s smaller) and the 1.7/1.8 turn up at the back so the rear hanger and muffler is specific t the type of exhaust that you have.

I ran a 2.0L SSI Heat exchangers on my 1.7L D-jet motor.
Yes the muffler and Heat exchangers and hanger must be the same.

Ok I can run 2.0 on my 1.7 with the 2.0 bracket and 2.0 muffler; the reason I'm asking the question is I may replace my 1.7 with a 2.0 at a later date. The question about running the hearders with no exchangers is my exchangers have seperated from my headers and living in the Houston area I really don't need heating. Is there a heat shielding issue without the exchangers? Thanks Mike

it would be better if the headers were coated, but if you keep critical stuff far enough away, you'll be fine ...
Andy