Well, you can do anything you want, but those recommendations are listed in order of most bang for the buck IMO.
What I mean as far as the fluid goes, if you wish, after the free oil changes etc, upgrade to Amsoil or other top rated fluids, including oil, trans fluid, brake/clutch fluid, antifreeze etc. If you read through a number of posted threads you will see the difference a quality fluid will make.
AMSOIL Products for the 2016+ Gen2 Cruze
As far as the tune goes, both BNR and Trifecta have been sponsors of this forum for some time and while there is an obvious rivalry, if you follow their instructions and do your due diligence, you should have no issues.
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The BNR/EFI Live tune review you've been waiting for.[/h]
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TRIFECTA: +44 WHP and +51 ft-lbs on Chevrolet Cruze 1.4T MY2011-2015 (Jan2015 Update)[/h]
As for the plugs and fuel, if your smart, you will do these prior to getting the tune. Both will in their own right increase performance, and I am pretty sure they are required for most tunes.
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Hesitation...GONE![/h]
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Premium unleaded?[/h]
The rear sway bar will change the handling of the car dramatically and you will instantly feel the difference.
(Yes I know he has a Gen II)
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How-To: Install Whiteline BHR93 Rear Sway Bar (2011-2016.5 Cruze)[/h]
The brakes are a no brainer. Always make sure you can stop before you go!