The difference is: You can only roll over the star roll over once per shot (unless it misses the gate flap and rolls back over it). The spinner shot is a Spinner. Spinners normally turn many times, possibly more than 10 turns. So, in reality, if you shoot the lit spinner with a good straight shot, you may stand to get more than 10K. And if your bonus is maxed out, then the star roll over and saucer may have little value to keep shooting them.

As to modifying, why would you want to when the playfield is screened with the values? Changing the value could be as simple as moving a single wire (like from 1000 point relay feed to 10,000 point relay feed).

Fortunately, Mars Trek has 6 digit scoring so it may be a bit difficult to roll it over as compared to a 5 digit game with a light up 100,000 lamp.

Spinners can really rack up great scores even when they are only worth 1000 when lit. Games like Wizard, Aztec, and Amigo are pretty much a one trick pony when you get the spinners lit (Assuming the games are properly dialed in.

On the subject of modification (and lack of playfield labeling). Growing up, Jungle and Wild Life were very popular and common games. In the Active West Bowling centers, someone decided to modify them so the center spinner (normally scores 10 points and indicated on the instruction card, not the playfield) instead advance the bonus and therefore scored 100 points. Instead of shooting for the star roll overs, we were shooting for the spinner all the time. Perhaps the modifier was a Genius! as it was very common for a ball, coming out of the spinner/bumper area to go SDTM more often than not (ten large playfield inserts down the middle seemed to cause some playfield warpage). Especially if you hadn't mastered the alternate flip save. So, it was probably reducing play times even though it may have been increasing scores overall (the same games had higher replay thresholds).

In another game center on another Jungle, someone had added a "Instrument panel lamp" to the score Card holder that said 5X Bonus which lit on the last ball (normally double bonus). I wonder where THAT game ended up and if the mod is still there?

This gets mentioned a lot. I don't play in tournaments these days. Isn't it normal for the tournament to establish a "Value" to ever special earned by the player? Like 50,000 or something like that. Obviously, a special IS an integral part of playing on an EM and early SS game. Maybe not so much on today's newer games with Wizard Modes etc. Tournaments should be awarding a set score value for each special earned. But, I guess it might be hard to keep track on a multi-player EM as to who's the replays are at the end. Not very hard on a single player, just clear them off before each player starts his/her game.