S-Type 4.0 V8 performance mods?

[Simon.Warren]

The performance of the big Jag can't be called slow, but it could do with a few extra ponies to liven it up a bit.
I have looked for ECU upgrades and cold air induction kits, but have difficulty finding companies that do them for the 4.0 V8 S-type.
Does anyone have some info where I can get this type of thing? Or any other advice to liberate some hidden gee-gees from the car?
Cheers

[P700DEE]

Paramount in Slough