Smelly Exhaust since 02 mod?

Hi all, I have a very (hopefully) simple question which has been bothering me for the last few days.

Since installing some 02 eliminator plugs on my 08 VTEC, I've noticed the exhaust smells a little. I'm presuming it's because she is running a bit richer? I haven't noticed much (if any) difference to fuel economy and she definitely runs smoother with them in.

Is this normal/safe to just use the 02 plugs or am I going to kill the cat?

Thanks for your time everyone,
Steve

 

Does it smell like sulfer?

 

Did you just do the elims, or did you install an FI module with them?

 

Hi I just installed the 02 eliminators (which I've done before on my old VTEC). It's not really a sulfer smell I don't think, more like a smelly inline 4 kind of smell!