Hi guys,

Currently one of my S1 engine's is running just under 200bhp with 18psi boost. It has a standard head and internals. I've been offered a stage 3 head. Can anyone tell me what power increase I could expect if I fit a stage 3 head? Also will there be any bad effects e.g increased lag? and will I need any remapping etc after fitting it, or is just a case of swapping the head and off you go?
Thanks very much in advance for your help.

S1Luke