The 8days is a great watch, but no way will he get one for 4-4.5k
I think Panerai prices will be slumping as the air goes out of the tires, even the previous 'good investments' are dropping in price like rocks... Look at the 192, has come down in price by 3-4k in the last year.
Bottom line, like Whatch-A-Doin? says, watches are not a good investment. They may hold their value (rare), but the ones that go up (if at all), and we can predict, are the expensive ones that are limited in production and they command a high purchase value in the first place.
I bought my 91 at a pretty good price, but that was a few thousand less than it sold for, I probably would get my mula back, maybe even a little more if I sold it, but I'll keep it for a few more years... It could be worth more then or it may be worth tiddleywinks... who knows... Look at some of the pricey ones now, the 036 and some of the Pre-As... I wish I got on the boat back then!