Actually, Tim, the LE, SE and SSE were the model designations before the SE, SLE, SSE, and SSEi started in 1992 (the SLE started in 1993 I think). There is no direct comparison per say. What I can tell you is that they are listed in order from lowest trim to highest trim above. I have an SE, which is to say that my car has fewer standard features than the SLE, SSE, or SSEi. An LE would have fewer standard features than the SE and SSE for that year. This does not mean that the SE or LE are not good cars. This just means that they have fewer things that can go wrong with them
Actually, mechanically they are all almost the same within any given model year with the exception of Superchargers, HD trannys, and suspention/performance shift type options. That is where it counts in these cars. The fact that they are well engineered and comfortable--even in there base models. Keep in mind that when your LE was built it was more luxurious than any other upper-end trim line Pontiac made.
One more thing, There has been a lot of debate about what the acronyms stand for (LE, SE, SLE, SSE, and SSEi). While Pontiac states that there is no meaning behind the letters, many members (and Dealers) have come up with there own interpretation of meanings that are pretty acurate. I will am not starting a debate--just giving examples--so PLEAS DON'T START DEBATING OR TURN THIS INTO A THREAD THAT IT WAS NOT INTENDED TO BE, Pontiac was very clear that these don't mean anything.
LE could mean Limited Edition or Luxury Edition--but it doesn't mean anything. The emphasis was that it was a special marque offering things not commonly found in other makes and models--thus Limited (which IS used to describe other models and makes that fit this criteria)
SE could mean Special Edition or Sport Edition--but it doesn't mean anything. the emphasis was that it was sportier than the LE, and in later years where LE was not offered, it took the place of LE as being the base model--yet still offered amenities not commonly found in other makes and models (again, SE is used extensively by GM and Ford--and may even be used by Chrysler--and means Special or Sport Edition)
SLE could mean Special Leather Edition or Sport Leather Edition (as a used car salesman at a Pontiac dealership once told me when I almost purchased a 1996 SLE)--but it doesn't mean anything. This designation is only seen on Pontiac Bonnevilles and some GM trucks. It is commonly known that most (if not all) SLE'* have leather interior. This would certainly lend support to this argument.
SSE could mean Sport Special Edition (or vice versa) or Super Sport Edition--but it doesn't mean anything. Again the emphasis was on the sports tuned suspension and sportier looks/feel of the car. It was the top of the line for the Bonneville in appearence and handling. SS was used on the Cheverolet line to distinguish its sportier editions.
SSEi could mean the same as above for the SSE with the "i" standing for "induced" as in forced air induction. Nowhere else is the acronym meaning more difficult to refute than here because the "i" is indicative of the only difference between the SSE and the SSEi--that of forced air induction
, or a Supercharger. But again, Pontiac is very clear that these letters mean absolutely nothing.
In Pontiac'* defense for claiming that these acronyms mean nothing (even to the distain and unbelief of most of us), they are now working on the GXP--which truely has no literal meaning. We could all work on a meaning such as Gran X Pontiac--but what would the "X" stand for? Obviously this is going to be the top performer for Pontiac--with GXP editions for many of their marques.
Will Wren is doing an excellent write-up on the history of the H-body Bonneville on his web page. If you would like more info, I would suggest visiting it and reading his Time-line. Very good stuff there.