If the trans is a 98, it will be stamped on the top of the bell housing "98" and there were some 97's that were tagged to show any technician that the updated accumulators and springs were NOT installed. The 98 is what it is. A 97 out of a 98 is a 97. Nothing special about it.
As for gaining anything by switching, no gain unless something is wrong with your current 95 trans. 93 thru 97 can be manually shifted but you're asking for it if you do. The 98's can be manually shifted and there is nothing to worry about, normally. All in all, as for gaining anything from any of them, it would be with the 98 because of the friction material, the one way clutch and being able to manually shift without worrying about it shuddering the next day or the the next month.
If you do swap to a 98, all you have to do is swap out the electrical internal solenoids and the main power harness wire. It would be plain dumb not to go ahead and j-mod it while you're in there because it only cost $5 to $7 to do it and two drill bits and a cordless drill. I'll provide the link below with pics on how to do an actual 98 transmission conversion into a 93, 94, 95, 96, 97
It takes a little time but not long and it is extremely simple if the trans is out and laid upside down. Even easier if both are laid side by side and upside down. I done this instead of the re-pin method and it worked like a dream on the 94 I had.
In the link, notice the first two top pictures of the dating and how the 97 should look if it's (accumulators and springs) only were not installed.
http://sites.google.com/site/krackerskrazy8s/94-to-98-tranny-swap
