yes, it does matter. for most quality brands, such as garrett, turbonetics, precision, etc, they use garrett made internals with their own compressor and turbine wheels and housings. the low qualtiy turbos, many of which you see on ebay, are made from unknown sources. some of those are decently made, many are not. a turbo spins in excess of 100,000 rpm, so absolute precision is necessary or the turbo will have problems. an improperly made or balanced turbo will cause damage to itself and your engine.