Wireless will cause tonal differences. The ones that won't cause a dramatic difference will cost a dramatic amount of money. Sennheiser SK50 to a 3032 receiver would be about the least expensive rout that I would go. The reason for the difference is the internal compander circuit and the EQ that has to happen to get all that info in to the limited bandwidth of the RF signal.Sennheiser, Lectrosonics and a couple others do a good job for instrument transmission. Most others don't.
Peace (Phil 4:7)