I know this is like compairing apples to olives; BRP's "cold side" for the 94-97 Miata's puts out about 170-180 WHP useing a M-45 blower, their MP-62 blower with an A/A aftercooler might make 200 WHP on the 94-97 with the bottom end being the limiting factor and the 99-05 MP-62 kits get up to about 220 WHP
All that being said, what are the weak links in the pre 04 S's and will they be able to handle the torque.
Untill they can one that is dealer installed AND dosen't void the warrenty, but thats just me.