Is the Zulu spoken in Durban significantly different from the formal textbook versions?

I’m planning a trip to KwaZulu-Natal and I’ve been studying standard Zulu, but I’ve heard that the urban slang and the influence of other local languages might make my classroom Zulu sound a bit stiff. Should I be worried about being understood, or is standard Zulu widely accepted enough that I don't need to try and mimic regional slang until I’m truly fluent?