I'm not sure where the issue would be connecting any info gauge in those years, I have a 96' GSX, just like the 98' is has connections for compass and air temp, but it's not used. Some of the info gauges from the vendor at the time had the extra features like a GTX would have but they were not used on the VTS skis.
My 96' didn't have a speed o, a compass, or an ambient air temp, but I was able to add and connect all of them because the wires are there on the gauge.
Get the 98' or whatever you find that has the VTS, it'll work.