What's the difference between the Mazda sport vs touring vs grand touring?

I appraise property damage for a living, and even though I probably look at 3 mazda's a week, I can't figure it out. The trim levels do not decode with the VIN, and the dealer cannot always tell the difference either. Is there anyway to distinguish these trim levels on the Mazda (I'm referring to the Mazda 3 in particular)? I've heard that it may depend on the grille (painted vs plastic honeycomb). Any thoughts?|||Check the mazda website or edmunds.com to determine the standard equipment. I believe GT has leather seats, Touring has keyless entry, sport doesn't have keyless entry. I think the body is the same. The 3s (which has the larger 2.5 L engine, compared to the 3i), has turn signals on the mirrors.|||More options become available as the trim level goes up (Sport-%26gt;Touring-%26gt;Grand Touring). Wheel sizes/styles change but that's about it.