You can just parent your player data to the default player type example:
datablock PlayerData(T_Bandit : PlayerStandardArmor)
{
maxHealth=80;
jumpForce=10 * 90;
jumpDelay=0;
minJetEnergy=0;
jetEnergyDrain=0;
canJet=0;
uiName = "T Bandit";
showEnergyBar=false;
};
This one will alter only what you see, the speed shall remain the same as the default playertype.
Also, don't expect help so quickly, you can also post coding-related help in the coding help topic and it will get answered quicker than general modification help.