Yes, the delay in getting a registration is a pain ... however, 3 months is a long time - mine (3 of them now) seem to come through in about 3 - 4 weeks. Usually, the shop you buy from will supply a 'For Registration' plate, but the police don't always find this acceptable!
What is better is to get a 'Permit to Travel' issued by the LTO. The local Mitsubishi agent obtained one of these for me when I bought the Pajero. When the police stopped me and told me that it wasn't legal, I pointed out that it was issued by LTO, so they muttered and let me go on my way. Two days later they stopped me again, but as soon as they recognised our faces, they just waved us on.
