difference between 01 and 02 1.8t gti..

i'm about to buy a 01 gti.. but it's got kinda way lower horsepower than 02 gti.. about 30 horsepower difference.. what is the difference?? anyone knows ?? is it just boost and ecu setup??

 

I thought they are all 150bhp! it could be a GTi but a none turbo! 125bhp 20v model!

 

wtf

 

I thought the later ones had 180bhp. I know they have vvt. Do they have bigger ports in the head and a different ecu? Wouldn't take much really.