os tz 5port
#2
yes you can with tz 3 port, but por performance, do so with 5 port as that crankshaft is a little bit wider if i remember correctly, besides it costs $7 more in tower
#4
no idea for this, but then, a speed crankshaft is expensive compared to stock 3 and 5 port, and then, you have spec 1 and spec 2 speed!
#6