Oranges can be modded by many ways... They are good, but sometimes guitar player need more accurate sound.
Prices for Orange mods are approx. 80-100 Eur (w/o shipment), it depends on many factors, mainly on elaborateness.
Orange TH30 mod
This mod is mainly for metal players: better bass response (more precise), more bite and aggression in the midrange, better reaction on player's fingers, better soloing... There are two TH30 mods at this moment - with big differences in sound...