Additional Memory, disk space and bandwidth

[sychern]

I would like to add Additional options for : a) Additional Memory b) Additional Space c) Additional Bandwidth d) Network Speed.

 

If client choose option "No need", it will follow default product confg.

If client choose to add 1GB ram, it will add 1GB to default product confg, let say for 1GB ram product,

it will become 2GB ram.

 

If client choose to add 100GB space, it also add it to original product confg(not replace it),

Let say original product is 50GB space, it will add 100GB to 50GB and total space is 150GB.

 

Any way to do that?