98 Metro 1.3 Exhaust
 

I was working on my friends and was looking at the exhaust LIterally like a 1 inch exhaust If you still run stock type muffler with 2 inch piping would it make any difference or would you lose too much backpressure?

Backpressure usually not an issue. Run 2" pipe max for best performance. Use a stock muffler or similar. These cars are loud!

Thanks for the info man do you know if there are catback kits for these cars? You seem to be the Geo Master

I don`t know how much horsepower the 1.3L makes but I would google exhaust sizing and see what you find. The smallest I have heard of for exhaust shops is 1-7/8 inch tubing. Most smaller displacement vehicles get that ricey sound from the exhaust. I would have a exhaust shop custom make me an exhaust from 1-7/8 tubing. The tubing more than likely going to be crush bent anyway and restrict the flow down which is fine because the tubing is more than likely slightly larger than needed. I would get a resonator and a muffler with as much packing as possible so it does'nt sound so ricey. I prefer a straight thru design like magnflow over other designs to keep engine pumping losses to a minimum.

Or, spend a couple hundred dollars and get a complete Walker system from manifold to bumper.
Then install it yourself on a Saturday afternoon.

What size exhaust does it need? Autolounge.net | Calculators | Exhaust Pipe Sizing
Because according to that calculator 1" is ideal for running at 3,000 RPM on a 1.3L engine to produce the most horse power.