[SLESTAK75]

I put the large valve head with p&p and milled from Syc. I put it on the stock jug and have been totally impressed with it. I say it is well worth the money I spent and let me tell ya it was HARD earned money. You will get an improvement with no other mods but not nearly as much as if you open the intake and exhaust. The new head will breath much better but if the rest of the intake and exhaust are still restricted then so is the new heads ability to deliver its best. There are some free and inexpensive ways to open up your intake and exhaust. Also adding an A12 cam for around $30 is well worth it. Have a look at the "gy6 150 most common mods" thread for some more info. And if you have any more ?s just ask.