Big thanks to CatadorDeLatas, I was able to change the Track Lineup to the GP Exclusive Tracks so you can play them in Practice Mode!
Here's a set of Patches that allow to play the GP Tracks in Practice Mode! Both patches have been tested and works with no problem!
Patch to an Unheadered (U) ROM and enjoy!
Patch 1: MC2, RC1, RC2, DW2, FF, WL2 and PT1
Patch 2: MC3
Note: I left tracks 2-7 in Patch 2 as is!