Canman, there are several posts in these forums that compare the M50s/40s and M60s.
randymans post
fhw post
sonicfox review
just to list a few.
Placing the speaker closer to a wall will typically enhance the bass more than anything. Several people on these forums, including myself, have limited space in which to place our speakers. I'm sure you will find something that will work to your liking. Six inches is not that bad.
As for subs, again there is fair bit of info on subwoofers and brands within these forums. Many people use a variety of brands alongside their Axioms including SVS, Hsu, Adire, Paradigm, Klipsch, Axiom, Sunfire.
Personally i've found some issues with my EP350 although others have had no problems at all.
port chuff
If any salesman is putting pressure on you to buy anything, i highly recommend you go to another store, or in the least, tell the salesman you don't like his pushy attitude and try talking to a manager. I've found they tend to be much better in reading a customer and not pushing them nearly as hard as a salesman trying ot make commission. Perhaps that is because most managers are on salary and not commission, who knows.
As for your Onkyo question, i am presently using an Onkyo DS797 receiver for my system. It was an excellent buy and has so far met all my expectations quite nicely.
