Well personally I'd go with the SP because I love the look of the M68 wheels that come with the SP. I think that with either the 17''ers on the SP or the 16''ers on the stock you are going to want snow tires in the winter. With snows I think the SP should be just fine.
The real question based on the two configurations seems to be whether you want a slushbox or you want to shift like a REAL driver.
