[Elecraft] K2 Addons - now or later?

[W5RCM - Ron]

I'm looking to build, at minimum, a K2 with KSB2, and add, over time, 
the K160RX, KNB2, KDSP2, KIO2, KAT2, K60XV, and KBT2.

My question is: which of these addons does it make more sense 
TECHNICALLY to build from the start?  It looks like the K60XV would be 
easier to add from the start, rather than have to go back later ripping 
out and replacing lots of components on the main board, cutting traces, 
etc, while adding the battery option is not different no matter when you 
add it.

The other modules, I imagine, fall somewhere in between the two 
extremes.  My reason for not wanting to buy all the mods at once is 
purely financial...all those modules together cost more than the radio.

Thanks for the advice, and you'll probably be hearing more from me!
-- 
72, Ron - W5RCM
w5rcm at volente dot us
Austin TX