They're listed near the top of the Inventory screen. The game is misleading most players by only showing the very best single items from each category.
Your total attack and defense ratings are made from the number of mafia members you have 'using' the best items from your inventory. So if you have 100 mafia members, 10 armored cars, 55 town cars, and 80 sedans, your total would be 10 armored cars, 55 town cars, and 35 sedans for the remaining members. Of course it would be better to have at least 90 town cars in this situation so that all of your members are using the best available items. It would be even better to have 500 members and 500 town cars, because you would be able to bring all of them into the fight. This is why mafia size is such a deciding factor in fights.
On the other hand, if you had less than 100 total vehicles and attacked or were attacked by someone, you would be using all of your vehicles but some of the members wouldn't be using any vehicle. The same goes for weapons and armor.
All the time I see people with 200+ mafia members and only a few weapons, so their 'best weapons used' list goes all the way down to 9mm semi-automatics. They would be better off buying enough chain guns to replace the lower items. After that, better items you get would replace the chain guns (or body armors or town cars) but that's still better than using inferior items.
A handy way of checking to make sure you're using decent attack items is to attack someone and click the Show All Items Used link near the bottom. You don't get to see this list for your defensive items though.
One more thing, attack and defense skills mean more than single points added to your mafia attack/defense strength. Sometimes I'm outnumbered and outgunned, but my Attack skill makes up for the difference in whatever equation or algorithm the game uses to decide who wins.