Hi Olly,
Cosworth stopped doing theirs from what I remember, it has been discontinued. Both Cosworth and Kinetix worked better with a turbo or supercharged car, not so much with the standar normally aspirated car in terms of performance.
Motordyne plenum spacer and stock intake with the velocity mod and panel filter would probably give you the best performance.
https://www.torqen.uk/118-plenum-spacers