for drifting, is it better to go single turbo or should i just upgrade my twins?

for drifting sequential turbos are better. less downshifting! you more power down low and better response that is part of the reason why i can't drift!

a small to medium single would be fine. Just keep the rev's up.

any turbo is fine just as long as you can keep the revs up i perfer a double tho for the extra power in the lower revs.