battlefield Birmingham 5 40k tournament

[Cookie101]

after the practise game with Dave against his sisters I think I don't need the lifta wagon between the lootas and deffrollas I had killed most of his tanks by turn 3, while the lifta wagon helped a lot, even killing one of his tanks turn 1 with 4 glances, I wonder whether a regular battle wagon with a super-kannon will be more useful.

a super-kannon stats is:
range 60" str 9 Ap 3 ordance 1 5" blast

so a super-kannon is still awesome against tanks, but it also useful against hordes of infantry and ensures that I don't have a 350 point unit doing nothing when there's no tanks on the board.

not only that but a super-kannon battle wagon is 40 points cheaper allowing me to get another grot mob in for another troops choice.

so 2 possible lists I can run

list 1: lifta wagon

warboss - mega armour, cybork body, bosspole, attack squig. pts = 130
big mek - heavy armour, kustom force field. pts = 90
6 mega nobs. pts = 240
battle wagon - 3 big shootas, grot riggers, deff rolla, red paint job, armour plates. pts = 145 (transport)

20 shoota boys - 2 big shootas. pts = 130
battle wagon - 3 big shootas, grot riggers, deff rolla, red paint job, armour plates. pts = 145

20 shoota boys - 2 big shootas. pts = 130
battle wagon - 3 big shootas, grot riggers, deff rolla, red paint job. pts = 135

10 grots + slaver. pts = 40
10 grots + slaver. pts = 40

5 burna boys - 3 meks. pts = 75
lifta wagon - 2 big shootas, grot riggers, armour plates. pts = 250

15 lootas. pts = 225
sky shield. pts = 75

list 2: super-kannon battlewagon

warboss - mega armour, cybork body, bosspole, attack squig. pts = 130
big mek - heavy armour, kustom force field. pts = 90
6 mega nobs. pts = 240
battle wagon - 3 big shootas, grot riggers, deff rolla, red paint job, armour plates. pts = 145 (transport)

20 shoota boys - 2 big shootas. pts = 130
battle wagon - 3 big shootas, grot riggers, deff rolla, red paint job, armour plates. pts = 145

20 shoota boys - 2 big shootas. pts = 130
battle wagon - 3 big shootas, grot riggers, deff rolla, red paint job. pts = 135

10 grots + slaver. pts = 40
10 grots + slaver. pts = 40
10 grots + slaver. pts = 40

5 burna boys - 3 meks. pts = 75
battle wagon - 4 big shootas, grot riggers, armour plates, 'ard case, super-kannon. pts = 210 (can carry 6 models so the burna boys still ride in this)

15 lootas. pts = 225
sky shield. pts = 75

which list do you guys think will be better and why?
any other improvement you guys can think off?