Size - 175/70/R13 for Cultus.
Brand - Any amongst Dunlop, Yokohama, Bridgestone, Michelin depending upon your liking and budget. Tyres are way to expensive these days.
Make sure the make of the tyres are not very old, week/year of manufacturing is written over there on every tryre.
Use original brands and genuine stuff only, do not settle for chinese copies and Taiwan's less known brands.
Drawbacks - none as such. But on the positive side you will get more road feel and pleasure drive plus comfort.