The MetaUtil class can be used for setting more internal stuff of minecart objects. For example, you can edit the name or the description (lore) of items.
There is a bunch of methods for changing the most common values of item stacks:
public static String getName(ItemStack itemStack)
public static void setName(ItemStack itemStack, String name)
public static List<String> getDescriptions(ItemStack itemStack)
public static void setDescriptions(ItemStack itemStack, List<String> descriptions)
public static void setDescriptions(ItemStack itemStack, String... descriptions)
You can get and set the name and the descriptions of an ItemStack. Every description entry in the list is one description line, so you can make unlimited description lines.
If you don't want to have the italic (name) and italic-purple (description) font, you can simply add
ChatColor.RESET before the name and every list entry. That will reset all formattings and you can use your own ones.