currently running stock s4 ngk's on a stockport s4 motor, would those suffice as replacements, or is there any that would be deemed an "upgrade"

 

The stock NGK's are generally the best choice for a stock engine. It depends on the engine, and ignition setup, as to which are best for your needs.
I am using stock 2nd gen plugs in my SP 12A. Some will say they aren't the best choice for a stock 1st gen ignition, but I haven't had any issues.

 

Just make sure you stick with NGK. If you have upgraded your ignition at all, like with the 2nd gen coil pack, then you might want to consider using 2nd gen plugs. But otherwise, just stick with stock...

 

i wouldnt use another plug besides NGK on any rotary engine...

its a second gen motor with fb ignition thats why i asked, u think gsl-se plugs would be a better choice?

 

NGK is a quality product. Stick with em.

 

SE plugs or S4 plugs either one will work.
The SE plugs are prolly the best match, with the S4 plugs coming in a close 2nd.

 

most anybody will say NGK is a must,

But please look at thread on using modified autolite plugs.
I dont remember the author perhaps rx7 doctor or peejey - youll need to do a search,
This plug was cheap great on gas mileage and gave by authors report best performance for his setup which if I recall was rather typical.

regards
two79rx7's