Scoobster,
99% of people think they need an MEP rating, and 99% of flight schools will tell them that as well, for obvious reasons. The (P) in MEP means piston - and most airlines use jets or turboprops.
The natural assumption is that you need an MEP to get an MEIR, but in fact the regulations state that you need to have completed the *training* for an MEP.
As for the MEIR - there are a multitude of ways to get it. You are right that a SEIR to MEIR conversion requires fewer hours, but that requires taking an extra full IR test, paying another full IR fee extra rental fees. Add to that - unless you're gods gift to aviation you'll find it hard to pass an MEIR test in minimums (which basically equates to one training flight in the aircraft and two in the SIM!)
At 167 hours you've definitely missed the boat on getting everything done in minimums - Am I right in thinking that you have 104 hours dual? That seems like an awful lot..