If you need to know almost every bit of Shigeru's Gameboy Stats, this is the place. Booster 136 gave me quite a bit of new goodies to show, so credit goes to him in the appropiate sections. If you're going to take some of this information, please state that you got it from Perfection. I worked hard on all of this, and if you steal this I will kill you.

Challenges

First challenge
Right after you recieve your first pokemon, he'll challenge you to try them out.

Second challenge
The next challenge is on Route 22, left of Viridian. This one is avoidable, but it's a good way to raise your pokemon's experience.

Third challenge
He's on Nugget Bridge. This one is unavoidable, you need to cross to get to Bill's house.

Fourth challenge
He appears at the end of a long corridor, right before the captain's office.

Fifth challenge
Fifth Challenge takes place in Lavendor Town, Pokemon Tower. He's on the 2nd floor.

Sixth challenge
This guy is the hardest, you can do many things to lose. Anyway, he's in that small room with the guy that gives you a Lapras.

Seventh challenge
We're revisiting Route 22 again, this time you have 8 badges and are going to Inidigo Plateau.

Final challenge
Final Challenge is at the Elite Four. He's Pokemon Champ and this time; you're the challenger! Beat him and you beat the whole game!

Red / Blue / Green

Pokemon
What pokemon lineup your rival has depends on the pokemon you chose at Ookido Hakase's lab.

Yellow

Starters
Shigeru shoves you out of the way to take Eevee, so that's his starter pokemon. Since Eevee has 3 evolutions, it's hard to say which one he'll choose Eevee to evolve. But here's how it goes:

If you lose to his first challenge, it evolves to Vaporeon

If you win, it evolves to Jolteon

If you win the first battle, but lose to the next (West of Viridian), it evolves to Flareon

Credit goes to Booster 136 for this info. No offense to Booster, but, if any of this is wrong, don't blame me. Here's Shigeru's lineup at Indigo.

Gold/Silver

Badge (Yay! Shigeru's a gym leader of Viridian!): Green

Pokemon lineup:

L:56 Pidgeot
L:58 Exeggutor
L:56 Rhydon
L:54 Alakazam
L:58 Gyarados
L:58 Arcanine

Pokemon Stadium

Gary/Shigeru is, like Red/Blue, etc. last after the Elite Four at Gym Leader Castle. This is his Pokemon lineup:

L:50 Exeggutor
L:50 Slowbro
L:50 Ninetales
L:50 Clefable
L:50 Electabuzz
L:50 Pinsir

Booster 136 told me that in Round 2, the level of your strongeset pokemon will be the level of all his Pokemon. (Example: You have a L:98 Mewtwo, all of his Pokemon will be L:98).