i would to say depends on your budget. for now u may say 135hp is enaugh but trust me, power will never enaugh. whahahah
for me, i would go for 4AGZE. 1st, your partially into force induction territory. with around 160hp qouted on engine, i think its going to last u long enaugh a moment. thn should u really go into turbo, all u need is some manifold, turbo and pipping works. moreover u do not have to worry about ur engine internal by that time which could save u alot.
im not saying 4AGE is not good, but the power is not there to compare. moreover u will need to invest quite abit on engine whn u choose turbo route.
since 4AGZE is still 1.6cc, u still able to enjoy 50% roadtax rate...!!! whahahahaha