I honestly would go big, or not bother at all.
That being said, I have a cam very similar to the S2X (though it has .010 more exhaust lift)
I love it. Stock idle tables it sounded good, had a great lope to it, but would sort of chug if just put in gear and didn't give it any gas.
Raised the idle up 100rpm, lost some of the lope, but is plenty streetable, gas mileage didn't change much at all, and it makes damn good power (revving mine to 6500)
Pros to the VS:
Smaller cam which requires less effort to run
Can usually find one used for cheap *which is because most people end up going to a bigger cam*
Cons to the VS:
Smaller cam so it doesn't quite have the HP potential of bigger cams
Usually will leave you wanting to go to a bigger cam
*IMO you should be replacing the seals, springs, and timing chain/dampener anyways, so it isn't really any cheaper*
Pros to the XP/S1x/S2x:
Larger cam, has more potential to make more power
Give the car a more aggressive idle (depending on idle RPM)
Larger powerband
Cons:
Slightly lower gas mileage
Possibly more expensive depending on what supporting mods you choose
Not *AS* streetable (depends on tuning and driving habits)
Will leave you wanting to get an even bigger cam and pretend you're a cammed V8
My opinion is, run the biggest cam you can afford, you don't really want to have to install a cam twice. It is doable in one day (mine took about 10-12hours from start to stop) Do it right once and be done with it.
I run a new stock chain and dampener
Comp Cams 76-802-9 cam
105 Crow Cams springs, intense retainers, ZZP's Viton seals
Idle bumped up 100rpms
Overall, I'm extremely happy with it. If I were to do it again, I'd go with an S3x, double roller, and 150lb springs with milled guides.