this question is often asked [like exhaust mods here]
The general consesus is Iridium, platnum and other expensive plugs are for long lasting NOT nessessary performance..The $2.50 NGK's are good...
Getting MSD fitted now and tuned for 55 Lp low impedance..AS the tfi module is stuffed adapting Bosch pick up and MSD digital igniter, coil...Having issues with keeping induction away from ecu wireing etc...But nothing that can't be worked out..
Should easily be around 375rwkw
BTW this means another turbo car[ebonnos] has some decent injectors from 24's up to 36 Lp..