Housing (cable 'sheaths') can stay put. I'd install polymer coated shift cables with both these groups. A single 6700 shifter might be pretty spendy through your LBS.
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"The older you do get, the more rules they're gonna try to get you to follow. You just gotta keep livin', man, L-I-V-I-N." - Wooderson
'14 carbon Synapse - '12 CAAD 10 5 - '99 Gary Fisher Big Sur