Only if his opponents have learned nothing and again get pulled into a boring (to voters) technical debate over the merits of LRT vs Subway.
The argument against the subway should be simple, and focus on the cost to taxpayers. Something like: "Rob Ford wants to spend $1000 of your hard earned money to bury the Scarborough LRT for no reason" ($1 billion / 1M taxpayers). Then every single time during the entire campaign that Ford mentions anything about saving money or respect for taxpayers, you respond with "then why do you want to take $1000 out of the pocket of every taxpayer for your boondoggle?" Bonus points for referring to it as Ford's gas plant scandal.
In my mind, re-opening the debate is a GOOD thing, because it allows another chance to make a point that needs to be heard and wasn't heard last time.
His opponents shouldn't even allow Ford to frame the subway as a superior option or say "Scarborough deserves subways". Nor should they bother arguing the merits of LRT, for that matter. The message should be simply that it's effectively the same goddamn thing, only his version runs underground and costs you $1000.
Edit: also, if he suggests it's a "streetcar" or something inferior to a subway, the simple response is "no, it's an above ground subway" and it can be compared to the above ground stretches of the existing subway lines.