Perhaps knowing the reasoning behind the "upgrade" can help a bit. Linear/v brakes are quite effective and efficient and can be easily adjusted, no matter the lineage (except those casted very cheaply or made from stamped steel). If for braking performance, try replacing just the pads for good ones (I prefer koolstops, either full salmon color or combo/ salmon-black compound), and replace cables for stainless, die-drawn ones from Jagwire, SRAM, Shimano or Clarks if in the EU.