If you just have general queries about this, you'd be better severed asking these questions over at /r/manchester.

Edit: It'll try and be a bit more helpful. Avoid the taxis, take the trains if have to travel some distance. Alternatively, depending on when you'll be coming you can even decide to explore the city on foot, but remember to bring a raincoat/coat. Use the tram to get around Manchester, get a weekend tram pass, it'll save you a bit of money. That being said, can I ask when do plan on traveling?