what to do first?
 

i bought a 06 duramax its stock i have a cummins im tuning up but the duramax is alot different then cummins i want the efi live tuner around 500 to 600 hp what needs to be changed first? especially transmission

A lot needs to be changed to get 600hp

the trans i would go with a suncoast GMAX6 kit or a PPE stage 5 kit

you need a bigger turbo, better pistons, better rods, bigger injectors, dual CP3's, lift pump, head studs, tie-rod sleeves

thats about all I can think of for hard parts

500hp you could get away with trans upgrades, little bigger injectors(to get the pulse width down) lift pump, and tie-rod sleeves, but it would all probably be on borrowed time

the duramax seems to be happiest in stock form around the 400-475 range, it should last there for quite a while

Hope this all helps:tu:

yes thank you besides efi live is a banks tuner good? or which would be better?

Efi live. Banks is good but efi live is unbeatable.

^^^^^^so true