I've dyno tuned my car and got some impressive gains. I'm using an A'pexi S-AFC II to do air/fuel tuning. Saturns tend to run way rich at WOT. By leaning the mix, you can gain some horses. I tuned for about 13:1. I don't have hot cams or headwork done but if I did, this would help out even more. With cams, the A/F controller can cure the rough idle.
Check out the gains or the dyno chart. I have great gains from 4200 to redline simply from leaning the mix. I also have a weird spike at 3800. I think that's a quirk with the 1.9 DOHC engines. I actually seemed to lose power on the later runs according to the dyno but that may have been caused by the engine running hotter and hotter air being sucked into the intake. The end result: it pulls harder. I've already gained .8mph in the 1/8 mile trap speed. That should equate to over 1mph in the quarter mile. I'll post new 1/4 mile times next time I go there.