This. my buddy just got an 07 700 dragon for 3800 and I've seen several 600's in the IQ chassis for well under 4k. if you all ride that same the boys will think its cool (i did when my dad and i had the same sleds) and your spare parts can be consolidated.imo i would find an 07 dragon rmk 155" for yourself.
and i would find two 07 rmk 600 155" for the boys
after watching what my buddy has put his 07 rmk 600 through and absolutely how poor he treats it, its amazing that it even starts and runs let alone still rips at 3k miles. that alone proves to me they are a reliable machine.