In the past the SRi models typically had different gearing and harder suspension than other models. That's no longer the case with the Astra K so the Sport button is the only step in that direction. It changes the feel and responsiveness of the accelerator and steering and is only available on the SRi (not available on the Elite even as an option).
The SRi offers the driver's assistance pack with collision alert, traffic sign recognition, lane departure warning with lane assist and distance detection via the forward facing camera. This is available as a £565 option on the Elite.
The SRi is the only trim to have dark roof headliner which reverts to light grey if you order the power tilt and slide sunroof. I think the dark headliner makes the car feel a bit claustrophobic but others like it.
The Elite has several standard features which are optional extras on the SRi: AGR ergonomic
driver's seat, electronic parking brake, electronic climate control, heated steering wheel, heated front seats, ambient front door lighting, electrically folding mirrors.
The Elite has some features which are not available, even as options, on any other model: AGR Ergonomic
passenger seat, leather seat trim (dark or light options), 2 rear USB charging sockets and heated outer rear seats.
The Power Front seats with driver and passenger ventilation and driver memory, power adjust and massage function is only available as an option on the Elite for £495.
The alloy wheels are different on each model too.
See the
New Astra Price/Specification Guide 1 January 2016 for full spec details.
You need to read it carefully to see that the details like the Parking Pack offers electrically foldable mirrors, the front/rear parking sensors add 6 speakers to Design and Energy models etc.