I bought one of these cars recently as a Japanese import, great combo of performance and economy.
Finding tuning parts in NZ is a struggle though, understanding what fits and isn't crazy money.
Remaps deliver approximately 60BHP and 70lb-ft of torque from the standard B48A engine , but there is always more you can squeeze out.
Here is the rundown of what I have found
Parts confirmed to work with this car are as follows
Charge pipe
$425.00USD inc shipping $640NZD ( there will be import tax)
Induction kit
BMW F3X B48 2.0L cool air intake system (BW-B4801) (mst-performance.com)
$497.20USD inc shipping $749NZD( there will be import tax)
Other items I will update
Panel filter
Down pipe
High flow cat
Replacement intercooler