Sadly its not that easy with the Rangie and its complicated Harmon Kardon sound system with all its amps and subs and things. A good auto electrician may be able to rewire a new sound system in in which case you could choose any head unit you like. The Alpine unit unfortunately doesn't have available spares to repair it any longer. You can try to source a used unit from a breakers or a specialist used parts supplier like Partsrange on ebay; keep the old one for spares! The Rangie sound system is best in its original form, so that's the route I'd take. The Clarion units from older Rangies, which can still be repaired, won't be suitable unfortunately as a direct swop for the Alpine. It isn't a straightforward swop so don't just try to plug in a normal car radio as it won't work.