By Viper
Max Power Modifier (Default 0005)
81076D43 ????
Power Increase Rate Modifier (Default 0001)
81076D4A ????
FFFF should cause it to decrease by 1

Power Never Increases
81076D44 1000
Power Never Increases (Alternate)
81076D48 2400
Power Never Increases (Alternate 2)
81076D4C 2400
Power Never Increases (Alternate 3)
81076D38 0801
81076D3A DB53
Don't Lose Power From Missing Buoys
811F5CD8 2400
Starting Power Modifier
81075888 2400
8107588E ????
81075890 1000
Miss Worth Modifier (Default 0001)
81076E1C ????
Misses Don't Count
81076E28 2400
Number Of Misses To Retire Modifier (Default 0005)
8107E30 340E
81076E32 ????
Out Of Course Timer Increase/Decrease Rate Modifier
811F6832 ????
FFFF is the Default. FFFE will make it go down 2 at a time, FFFD - 3, etc. positive nummbers like 0001 will increase it.

Out Of Course Timer Doesn't Count Down
811F838 2400
Disable Out Of Course Timer
810750E8 2400
Lap Timer Doesn't Run (Stays At 0'00'000)
81077738 2400
Stunt Mode Timer Increase/Decrease Rate Modifier (Default FFCE)
8107827A ????
Stunt Mode Timer Doesn't Count Down
81078284 2400
Stunt Mode Timer Starting Value Modifier (Default 3A98)
8107596C 3418
8107596E ????
P1 Codes
Watercraft Modifier P1
800DB8FF 000?
Activate this Character Modifier by pressing and holding joystick in up position while at watercraft select screen.
0 - Watercraft #1
1 - Watercraft #2
2 - Watercraft #3
3 - Watercraft #4
Course Modifier
800DB90F 00??
With this code, it works in all modes except for Championship Mode!
00 - Dolphin Park
01 - Sunny Beach
02 - Sunset Bay
03 - Drake Lake
04 - Marian Fortress
05 - Port Blue
06 - Twilight City
07 - Glacier Coast
08 - Southern Island
Costume Modifier P1
801CF631 000?
00 Regular Costume
01 2nd Costume
Power Modifier P1
801C39A3 00??
Infinite Misses P1
801C39AB 0000
Infinite Time Stunt Mode
801C3B3A 00FF
Always Place 1st
801C387B 0000
P1 Lap Timer Below 0'00'10
811C3A12 0000
Start On Lap Modifier
801CC24F 00??
01 - Lap 1
02 - Lap 2
03 - Lap 3
04 - Lap 4
05 - Lap 5
06 - Lap 6
P1 Have No Laps To Race & Always Place First
801C3877 0003
801C3B97 0003
P1 Infinite Time Out Of Course
801C3B5F 00FF
99 Points
801CC27F 0063
Score Modifier P1-Stunt Mode
811C360E ????
Open Difficulty Modifier
801CC1BC 00??
01 - Hard
02 - Expert
03 - Hard & Expert
10 - Dolphin
11 - Dolphin & Hard
12 - Dolphin & Expert
13 - Dolphin, Hard & Expert
Open Level Modifier
801CC1C7 00??
02 - Sunset Bay
03 - Above & Drake Lake
04 - All Above & Marine Fortress
05 - All Above & Port Blue
06 - All Above & Southern Island
0D - All Above & Twilight City
16 - All Above & Glacier Coast
Automatic Retire
801C3B60 FFFF
Lap Counter Stays On-Screen
801C3B7F 00FF
Infinite Race
801C39AB FFFF
If you miss a single arrow then you'll be disqualified, but you can still race for as long as you wish!
P2 Codes
Costume Modifier P2
801CF633 000?
Power Modifier P2
801C3FC6 00??
Infinite Misses P2
811C3D22 0000
P2 Lap Timer Below 0'00'10
811C3D8A 0000
P2 Have No Laps To Race & Always Place First
801C3BEF 0003
801C3F0F 0003
P2 Infinite Time Out Of Course
801C3ED7 00FF
Watercraft Modifier P2
800DB903 000?
Activate this Character Modifier by pressing and holding joystick in up position while at watercraft select screen.
0 - Watercraft #1
1 - Watercraft #2
2 - Watercraft #3
3 - Watercraft #4