For that era, Based on what I know now, it would be road bikes not MTBs. MTB tech was still in its infancy.
I would select the best performing component group, Shimano Dura-Ace 74xx. It left everything else for dead, period. Next would be my sentimental favorite, best friction group: Suntour Superbe Pro: gorgeous precision. Although I love Campy C-Record's beauty, it just didn't measure up in any performance point and had annoying technical issues.
It would go on a Columbus SL tubed frameset, preferably Italian production, Ciocc, Colnago, Basso, Billato, Tomassini etc; next Merckx production, then Canadian Marinoni. Finally, one of the Schwinn Columbus SL production framesets as third.
I really like how SL rides. And IMO, SLX would take away that magical feel SL possesses for my non-racing pursuits.
Alternatively, Tange Prestige tubed frameset is my second choice. Rivals Reynolds 753 in strength and lightness. I don't know what production offering used it in 1988 as it was rather new.