He should be able to go 12's on that setup. Don't mod the car any further until he does

Put in some race gas and crank up the boost to like 22psi, drop tire pressure to about 15psi, and then then SHIFT EARLY! 14b/16g isn't making much power after 6k, search around this forum for good shift points for that turbo/setup.
Then teach him to be responsible with the car, respectful to other people on the road, and polite and extra respectful to the police! If he is not, he will loose his license in a hurry and none of this will matter.