Re: what should i do with the RG320?
To my knowledge, the RG320 has a basswood body with a quilted maple laminate. If the guitar has powersound pickups in it then it's a pre-2005 model and I'm not sure what bridge would retrofit with the EPII. If it were a 2005 model then it would have the Infinity pickups (a vast improvement over the powersound pickups) and the Edge III trem (which can be retrofitted with an Original Floyd Rose). Pickups are easily replaced, but trems are not. Honestly, you're probably not going to get much for the guitar if you sell it (with it not being Prestige or anything like that) so I would probably keep it, block the trem, and swap the pickups. If you're really wanting to have a guitar with a useable trem then I would start saving up for one of those used RG5xx guitars or buy a new RG1570 or other Prestige Ibanez RG.