Andrew-
This is a tricky one as there are four (4) main OEM Porsche variants of sport seats that will easily fit into the 968:
1) Early softback sport seats - found in 944's and early 968's. Based on condition and options, expect to pay between $750-$2000 for a set. These seats have the horizontal 944 stitching pattern. Seats needing a full recover should be had for less, IMHO. The seats have raised or extended side bolsters on the back and the bottom.
2) Late softback sport seats - found in late 968's and early 993's. These are more rare I believe and command a bit of a premium. Based on condition and options, I would think you'd be looking at at least $1200 to $3000. Full recover sets could potentially be had for less, but I think that's a real serious long shot. These seats are identical to #1 above except for stitching pattern.
3) 968 CS hardback sport seats. The lightest and "sportiest" by far, fixed back. Also the rarest. I think you'd be looking at a minimum of $2000 and a max of $4-5K based on condition. Good luck finding a reasonably priced, good condition set. These seats are nearly identical to the Recaro Pole Position, as they are based on them. There are a couple minor differences between the 968 CS seats and the Pole Positions, which most people don't know about.... Only the trained eye would really know. So if you're after the look, save yourself a few grand and get the Pole Positions.
4) 993 hardback sport seats. The heaviest and also the "snazziest!" A lot of 993 guys worship these seats. They definitely look nice. Figure on $2500 to $5000 depending on condition and options. They really don't hold you "in" like the first three do. That said, if you're wider (large waist/torso/etc.), you may not be comfortable in 1-3.
In my opinion, the 968 looks right with any of the first three choices (the difference between 1 and 2 of course being the production date). #4 works, but I am not 100% sure they would look proper in a 968 in my opinion.
Any of these seats are basically plug and play for the most part. The CS seats require speacial sliders, so if you stumble upon a set of them, you'll either need to verify they are included or buy a set from a Recaro dealer (I think they are around $300 or less for a set). The other three will bolt right up and also connect to the existing plugs for the electrical goodies if so equipped.
There's also 993 RS seats- which are like the 993 hardback, but are totally manual and lighter IIRC. Really expensive and over the top for a seat that technically isn't suitable for its pervceived intention. You can also use 964RS America seats - basically the same as 968 seats with some differences.
Then,

if you really want to explore all options, sport seats from the Boxster and the 996 can be adapted to fit.... The seats (which will easily fit into the 968) up to and including the 996 were manufactured by Recaro if I am not mistaken. 997 and forward are made by Lear I think.
Hope this helps.