Atlantis says he doesn't have the problem (or, at least, not nearly as bad as everyone else), and he has an F-Sport Intake.
(Ignoring the fact that chrismiass doesn't have the problem either, and he has a 2006 IS 250 - possibly not with an intake mod ...)
Is it possible that an intake change, without any exhaust change, could also fix the problem?
There is some theory to support this, as an intake would change the air/fuel composition going into the engine, so it's possible the sulphate composition (sulphur dioxide/sulphur trioxide mix) would also be different leading into the exhaust system, perhaps making just enough difference to reduce the levels of sulphur build-up in the cat and/or hydrogen sulphide released from the cat.
But, to prove this theory, most people with an intake mod and no exhaust mod (and most owning an F-Sport) would have to say they hardly experience the rotten egg smell ...
Why would one care, if we know fixing the midpipe resolves the problem? Only that, if given the choice between an intake and exhaust mod, most people here would prefer the intake (refer to the "favorite mod" topic elsewhere in these forums) ... If changing the intake fixed the smell as well as added power, it would be a bonus.
I got an K&N intake kit on mine and still get the eggy smell - even with all the vents closed and it on recycle.
Tried various fuel - doesn't get better or worse as its still there..after you give a boot full.
