Depends on your current set up. Lotus Newcastle upgraded mine from 240, all I needed was ECU and software, fuel pump and adapter. I already had the injectors installed and a trd airbox. If you contact Lotus Newcastle or Christopher Neils I’m sure they could help you out.
I had the same response from Lotus (factory) when I enquired and they also recommend their Stage 3 exhaust.
To go from my 240 spec car to 260, the parts required in my case were as follows:
My uprated denso pump has a grey bottom instead of gold/brass. The top plastic section is much larger. Look on the seriously lotus website for a side by side comparison.
Hmm, I’m a little concerned that I have been swindled. The base of the “Uprated fuel pump” I purchased is gold/brass. Will have a look to seriously lotus website