As most Infection people know, kit Elite and kit Supreme have the same armour. The only difference between the two kits are their swords. Now considering the cost from Elite to Supreme (second most expensive single upgrade), you're not getting that much of a difference for that amount of money. This suggestion is to give kit Supreme an enchantment for their armour. Now since God armour already has protection I, Supreme will get other enchantments. Since prestiged people can get fire aspect and also a bow and arrow(s)+, the enchantments should be Fire Protection and Projectile Protection. If it was only one, the kit would only be useful against a fraction of the players, but with both it will be useful against two fractions of players. Another possibility is to add Protection I to only a few pieces of armour on the supreme kit, such as only to the chestplate, or to the boots and helmet.
Support. KB1, 2 hour advance on xp bottles, and a few more bottles isn't worth the upgrade for any supreme who plays infection most of the time.