If anything's going to head to head with GT4 it's Forza, and we already know which way that battle will go
Besides, much as we might hate to admit it, GT4 will make a big splash but I don't think it will be a sales leader for Sony. NFSU2, the 2005 EA titles, GTA - those will all sell well into the multi-million copies. A quick scan of game preview sites shows very little mass interest in GT4. GT4 will eventually make headlines for being so good at what it does, but I doubt we'll draw the interest we might hope to.
Besides, much as we might hate to admit it, GT4 will make a big splash but I don't think it will be a sales leader for Sony. NFSU2, the 2005 EA titles, GTA - those will all sell well into the multi-million copies. A quick scan of game preview sites shows very little mass interest in GT4. GT4 will eventually make headlines for being so good at what it does, but I doubt we'll draw the interest we might hope to.