If you want ExVeemon,MetalGreymon,and Stingmon...the only way to get them is choose the second pack.
You can get R-Booster 01 by having 23 Booster 1b.

At the level 5 you get champion,20 you get ultimate,and 40 you get MegaUltimate.

If you want your digimon got the ultimate form before you find seiryu city you can train your Digimon at the Plug cape,(west from central park)of course until your Digimon reach level 20.

After you defeat coelamon(at the Plug cape)you can get water chip..keep trying until you get it.

You need TNT ball to continue your journey..then defeat Triceramon at the Plug cape(he was uphill)

Go to the plug cape and go down, you will see a boy kicking a tree, and then you must have tree boots to kick the tree (to find cardmon). Then find the gabumon card at Asuka inn (go downstairs)and give the gabumon card to the boy at the plug cape. After that go to lamb chop and talk to the lady near the front door, she will say veemon is at the wind prairie. Veemon will hide in the kicking forest. You can find Veemon south after you go inside kicking forest.

Find Veemon:
After talking to Veemon at wind prairie, after you enter the kicking forest, Veemon will be to your left. You won't be able to see him because a tree is in the way, but you don't have to walk down that far at all, he's pratically at the entrance.