The Metro was built by Suzuki. With minor exceptions, all 1989 to 2001 Geo/Chevrolet Metros and Suzuki Swifts are the same car. All engines from the 1986 Chevrolet Sprint until 2001 will interchange. Your choice of engines are;

• 1.0L 3 cylinder (55 HP) used in Sprint and Metros from 1986 until 2001
• 1.0L 3 cylinder Turbo (70 HP) used in 1987-1988 US Spint Turbos and 1989 to 1991 Canadian Chevrolet Sprints and Pontiac Fireflys
• 1.3L 4 cylinder (70 HP) used in 1989-2001 SOHC Suzuki Swifts and Geo/Chevrolet Metros
• 1.3L 4 cylinder (100 HP) DOHC used in 1989-1994 Suzuki Swift GTi/GT's

Obviously the best engine would be the 1.3L DOHC engine. These are quick cars because they only weigh 1700 pounds. Aftermarket engine parts are not hard to come by if you don't mind paying the shipping charges from Austrailia. The best transmission is also the GT trans as these have slightly better synchros and a 4.10 final drive. Even with this high reving engine (7000 RPM redline), mileage is still a respectable 35-36 MPG. I still have a Geo Metro convertible in MI that I haven't moved down here, as well as three GT engines. I plan at some point making a hot little car to give some of the Miata guys fits.

This is a picture of my SCCA ITB car I raced from 1996 to 1999.