Lets agree that, BJP is outspending Congress by a huge margin and their media managers have made very effective use of this spending power. With that as a background, here are a few thoughts for you to consider
Gujarat has certainly grown fast over the last 10 years (next only to Uttrakhand). However 10 other states have outpaced it in growth over the last 5 years (period for which data is available). So while there is much to like about what is called the Gujarat model (frankly, other than a few anecdotes, I know nothing about this famed model), it is certainly not the only 'model'. Gujarat still has prohibition(although per reports there is a 30K crore grey market). Therefore its tough for me to reconcile with the Gujarat model, if I have to buy my weekly fix through the grey market, although my spouse would be happy if it implemented nationwide.
Lets also agree that in cities (certainly the metro cities in North and West India) there is certainly a Modi 'wave'. But it may be imprudent to completely write off Congress for a couple of reasons
1. Anti incumbency vote may get divided between Modi and AAP
2. Congress Government has done tremendous work outside of the main cities in the areas of Education and Healthcare over the last 10 years. Initiatives like NREGA, despite many chinks in execution, are providing livelihood to many and part of the enormous work done on 'Inclusion'. While Congress has failed to highlight this in the media, there is bound to be some goodwill from these initiatives amongst people that have benefited from it.
In any case, if Modi does win, his party may not be the one celebrating over the next 5 years, because it may turn out that the incumbent government is not really more corrupt that the previous government by his party, as is the popular perception. But that this, popular perception, is a result of the tremendous increase in media spotlight/CAG activism over the last few years, This is likely to get amplified even more in the coming 5 years because of the huge expectations being built around him.