Are you open to radical changes?
first let's look at your boyz... with a unit of 20, your opponent has to kill 11 boyz to force a test and possibly send the unit fleeing...
for 3 units, that's 33 kills to get rid of 60 boyz
2 units of 30, each require 21 kills before they test... that's 42 kills before they can send off the same 60 boyz
plus your points cost is 25 less (a unit of 30 boys with 3 rokkit, nob, klaw and bosspole is 250 each)
I'm on the fence on the ard boyz... I would take 2 units of stormboyz, then ditch the truk and get the numbers up to over 20..
a lot of people diss the boyz, but I kind of like the idea of 2 huge units of slugga boyz with rokkits and
pk nob followed by a big unit of ard boyz with shootas and rokkits... I don't like only 12 boyz, because it only takes a few kills to get your leadership down to where you can easily fail it.... and more than likely, your truk WILL be destroyed and you'll take casualties from that....
I personally feel that kommandos get killed so fast they're a waste of points, and the meganobz will have to test when the truk is destroyed, and they are so overpriced
I highly recommend another unit of lootas, max out your stormboyz and consider another stormboyz unit to add some more fast attack
the lootas have proven to be reliable skimmer/light tank killers, but one unit is easy enough to wipe out... 2 units gives your opponenent that funny feeling in the pit of their stomach

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a looted wagon would add some more firepower, and draw some fire away from the lootas
so if you were to drop the truk and take 20 ard boyz with shootas and 2 rokkits, that's only 20 points more
take 2 units of 30 boyz instead of 3 units of 20 you save 25 points
drop the kommandos and mega nobz, add another lootas, max out your storm boyz and either add another small
stormboyz unit and a looted wagon or max out another stormboy unit.... you should have lots of firepower and a
WAAGGGHHHH that will take a lot more kills before it takes a test
go boyz!