if i were you i wouldnt waste my time on the z6 head. you have almost 300k on ur bottom end dude how much longer do you think it will last after you put another 40h.p. on it?? trust me not long. if you dont want to do a full motor swap they are right thats the way to go but i would do the head swap and sell the car a.s.a.p.!!! it wont hold up for long.also you will need a vtec solenoid and a td-42 distributor and optimally a p06 ECU.if you really want to do it right just go to Hmotors.com and have a motor shipped to you from japan for like 550$ and only has like 50k miles on it. have fun and if you need anymore advice hit me up. i am in ur current predicament/build just a few steps ahead. sometimes i wish i had just bought the motor but i want the experience of building ground up!