I'd stick to your guns on that one. The art defines the flavour and I'm guessing you don't want the setting to go all manga on you. It's a style of story and character as well as a style of art. If you create the art but not the flavour to go with it, then your audience isn't going to stick around - and the people you would be targeting are likely to be turned away by the manga art and not read the text which they would otherwise be interested in.