The $250 shipped price was intl. version, not JP. If people are paying $100+ for the JP version, that's new in the last 18 months for sure. IIRC, it was you or skykid who posted in the what's it worth thread the difference for Intl or JP as I had both and was looking to sell one. The consensus was JP is about $15-25 more at that time, so I sold my JP to poodude for $275/shipped. Maybe the JP has changed, looks like it, but I stand by the Intl version at $250. el chuddo just sold a JP version, with copy arts, and shipping included for $350.
Guwange was 44,280 on Tops about 4 mos ago - I know because I bought one. It's up to 51,840 now, but the CAVE stuff at JP shops fluctuates rapidly as you know. Just 2 weeks ago we grabbed lantus a Galuda for 28,000jpy, 2 weeks later it's 37,800jpy.
The OP is looking to pay forum prices, in the US. I wouldn't offer more than $250/intl for RaDe or $450-475 for Guwange and I'd think with moderate patience he'll get hits on both quickly at those prices.