Howsit Reese130,
The cats are part of the headers, and you will have to change the headers to get rid of the cats.. Not sure what aftermarket headers are available in SA.. will have to check on that. Another option, take off the headers, cut the cats, take all the shit inside out and weld it back and fit...
Motor Plan will fall away if you change the headers.
Software is available for the 130i, contact Sherwin from Exceed to find out more..
To keep the motorplan and mod, BMW performance goodies are available but they are damn expensive..
otherwise, 50shot NOS and you away, when it breaks take the nos out and send to bmw...