Base model is the SE. Just the basics, but could be optioned up. Base body cladding and trim, usually cloth, sometimes bench seat with column shift. Base instruments.
Next is the SLE. Added leather, and a few other goodies. It wasn't badged in the first half of the 90'*, but was later, as it replaced the SSE as the mid-model in the lineup. From 95-97 it COULD be had Supercharged. The one in my sig is a rare example of the MOST you could get in one, including FE2 suspension, L67, CCR, ELC, Leather, Sunroof, etc. SLE'* have slightly different body cladding, and when the SLE replaced the SSE, it got the SSE/SSEi cladding on the exterior.
The SSE is typically thought of as an SSEi without the SC, but it could be had with the SC in the first few years of the 90'*. It shares the body cladding with the SSEi, and was replaced by the SLE in the second half of the 90'*.
SSEi has it all, and ALWAYS has the SC. They COULD be ordered down. You could get cloth, non-AL7 seats and a few other things, but it'* not common to see them optioned down, and most options couldn't be deleted.