As a general rule of thumb, it is pointless changing to a new arranger only one generation after the arranger you already have, as the differences will not be that great, but instead wait for the 2nd generation of the arranger you own, as this will usually be a much bigger and worthwhile improvement. (For even more variation also look at arrangers where the manufactures provide new features and sounds via a software/firmware updates, (Which is much better on the wallet) instead of forcing you to buy a new arranger to get them (Will be interesting to see what Korg adds to the PA4x in the future))

Regarding amplification/PA then this is the only way you will ever get your arranger to sound anything like the demos you heard of it, as the recommended sound systems fall far short of what’s required to get the best out of it. (Unfortunately most good sound systems are not domestically acceptable, hence the reason there are always multiple complaints about the sound from the owners shortly after launch)

Bill