I have plenty of Super 8 film stored in their normal plastic cases in relatively cool and dry places since the 1980s. They are in nearly new condition (especially since most is Kodachrome). Even my E160 (Ektachrome 160 G) films appear to have no color shift yet that I can see. Unless your film was poorly stored (damn, hot, extreme changes in temp, etc) they should be in fine shape. Like Perry suggested, started to unreal one just a bit. If it's flat and pliable with no signs of fungus it's likely to be as good as it was in the 80s.
I would go with any of those except the HD Spirit which will have very poor results with Super 8. They don't deal well with jitter or any warpage, etc. The Director would be a great option if you can find one that does Super 8. But, only the newest 10K version does Super 8. So, you might have a hard time finding that. Your best solution here in the US is the ScanStation (unless you can find an Super 8 Director which is HDR and full RGB).
2k or 4k?
Definitely 4K... or, as I do, the fully 5K overscan that includes the frame lines and perfs. This allows you to do your own re-framing and image stabilization as you see fit. It also allows you to export to your desired final media be it HD, 2K, 4K, etc. It's true there is not 4/5K of "image data" on Super 8, but there is 4k/5k worth of film grain to correctly resolve. You might not gain "resolution" but you will gain "sharpness". Plus, as Perry pointed out, if you ever plan to have a 4K media output you don't want to be upscaling... always bad.
I have worked with nearly all these companies (except Roundabout) and can say the overall experience with Perry at Gamma Ray Digital cannot be beat. Between cost, quality, turn-around, dedication and willingness to answer questions or concerns, they are the best.
Again, if you can find someone with a Director 10K and a Super 8 gate, HDR is totally worth it for film prints/reversal. The subtle detail and reduced noise in the shadow areas is very noticeable. Otherwise, the ScanStation does a fantastic job. I send all my Super 8 to Perry at Gamma Ray... and trust me, I've been around the block.
This is the most recent Super 8 reversal scan I had done with Perry: