There are two basic body styles, 89-94 an 95-01. Actually there are subtle differences in each series. The 89-91 cars are similar, and the 92-94 cars are similar. The 94 and 95 electronics are very close across the body change-all these cars are OBD1. Starting in 96 they became OBD2- this means they have a crank sensor to monitor missfires and a second O2 sensor to monitor cat efficiency. 95-97 cars have blinkers in the front bumpers the 98-01 cars have blinkers in the headlight assemblies.
Unless you are very competent with automotive electronics leave it alone.
If you want to make an “xfi” in the newer body style you can change the gear ratio by changing transmissions and put an “xfi type cam” in your engine.
The Xfi had a 9% higher gear ratio and an economy grind cam with advance built in. This is compared to the base model. There are 4 different final drive ratios available in the “Metro” transmission configuration. There is a 3.5, a 3.8, a 4.1 and a 4.4. The 3.5 came with the 1.3 liter 4 cylinder in the early car. The 4.1 came with the 1.0 liter 3 cylinder in the early car except the xfi and it had a 3.8.
The 3.8 came with the 1.3 liter in the late car. The 4.4 came with the 1.0 liter in the late car.
Of course there was the Suzuki Swift Gti and it had a dohc 1.3 liter and it came with the 4.1 ratio.
I played with these cars for 8 years and swaped engines and transmissions several times. I installed a 1.0 liter into a late sedan, they only came with 1.3 liter 4 cylinders. I installed a 92 1.3 into a 91 1.0 liter car, this required complete wiring harness swaps and mating the 91 dash to the 93 car harness. I do this kind of stuff as my day job.
http://ecomodder.com/forum/fuel-econ...cations.php#53
This is the 95 that I installed a 1.0 three cylinder and a 3.8 tranny. I installed an economy cam and a +10 gear. This car was a gutless wonder but got low 50s mpg on my commute of 60 miles per day. I installed a stock 1.0 and a 4.1 trans and the car drove fine. I gave it to my oldest grandson and he drove for 5 years until destroyed a year ago. The car got mid 40s with the stock engine and the 4.1 trans. This is the big body 4 door. The early cars are quite a bit lighter but the late cars have an airbag.