What is the best upgrade turbo (K04) 2002 audi a6 2.7L turbo for the price if I want to keep the cost down?

The turbos died on our 2002 Audi a6 2.7L. We have determined it is cheaper to upgrade from the KO3's that are currently in the car to KO4's. The problem is there are so many manufactures and we are trying to keep the price under $1500US for the pair. Any suggestions?|||Go on audizine.com, there is bound to be someone who has K04's for a decent price. Just a fair warning, this engine is one of the worst for maintenance and reliability.|||K04s are too big for a twin turbo set up on a 2.7L engine you would have increased lag and slow spin up it is the equivalent of putting a K04 on a 1300 cc engine, I would go the other way and look for K02s but you must have water cooled, try reconditioned ones from a reputable re-builder, a better solution would be to fit a blower|||Refurbish the one you have and add a bigger turbine and get it ported and poished for less than $1,200