Its a good list you've got there!
good solid and strong units, but it seems like your trying to shoot a fair bit with it, i'd drop the shoota boyz if you can and take more standard boyz if you can get em in trucks that way you can get em there quick! cos the trucks are fast you can deploy on the 12 move 12 and then turbo boost a further 12.. oh look your in your opponents deployment on your turn one and your boyz have arrived relatively safely!
i'd maybe drop down to 3-4 mega nobz as well that way you can afford to get them in a truck cos models in Mega armour just take up 2 slots which means your Warboss and his posy can arrive on your opponents door step along with the boyz to back em up!
Deff koptas are just nasty little things especially with the rokkits so good choice there and the jets another good choice!
the killa kans you could maybe save some points on by just giving them all just additional close combat weapons and just run the suckers behind your tanks to get obscured saves and stuff.
hope some of that helps