So the PSP is actually a bit different from the other version, and by that I mean differences other than load times so I'm going to list the differences here.

1. There are two exclusive characters in this version: Mappy and Mr. Driller (Neither of which are faster than Toc Man), due to this Pooka and Fygar are already unlocked.

2. there are two exclusive game modes, one where you have to collect pac-dots and one where you have to collect letters to spell Pac-Man.

3. There's an exclusive race, Subterranean Speedway which takes around 5 minutes and isn't a very good race in my opinion.

4. There are only 6 people in a race instead of 8.

Now that we're done with the noticeable differences let's move on to the small changes.

5. There are 4 cherries in Rolling Hills instead of 2.

6. The shortcut in Ghost Mansion is shorter by approximately 4 seconds.

7. The crabs in Pirate Cove don't exist.

8. There are only 2 worms in Galactic Outpost

That's really it for differences, if the extra race didn't exist I'm pretty confident that this would be the fastest version of the game. If I find anymore differences I'll add them.