e60 530d to e46 M3, fair price?

[CS111]

Hi, have been offered a straight swap for my jan 05 530d sport 53k for a late 04 E46 M3 SMG convertible in Estoril
The M3 is fully loaded, satnav , tv in motion, grey leather, Hardtop ......... It has 48k and had its 1200 mile service
Both cars mint etc etc Dotn really want to drop down a year, but realistically it is a few months
I take it the M3 would hold its value better than the 530d in a couple of years when comming to sell?

Fair deal?

[thehos]

i think i would put both of them in on parkers price guide and have a look see