+1 for http://www.raceimage.com/. I'd rather wear a used, professional quality suit than the cheapest suit that meets the spec but is brand new. Professional suits are way more comfortable and built to a higher standard. Plus you get to spread the love of bowling!
There's no issue getting one slightly larger than needed, but big issues if it's a bit tight. I bought a spare suit for fueling that has turned into the team's 1st-race-loaner-suit-for-new-drivers. It's fits a very wide range of medium and big guys (size 50/36/29) yet us medium guys never notice it is oversize. Remember, you're wearing it while sitting on your ass. All the 2 piece suits I've seen have velcro tabs for adjusting the waist.
Low Road Racing: Stylemaster/Mustang II/Sunbird/Spirit AMX
We will not compromise our morals and build anything but a class C car.
"You take the high road, we'll take the low."