i would opt for the Cossie duratec. or any duratec. better clock than the zetec, svt or not. read up on blatchat.com for thoughts from the larger community.
if u start performance optioning an SV, u end up near the price point of a CSR. the extra rigidity of the CSR make it more viable, even with a lesser engine.
the CSR comes with the big brakes standard, so thats a bonus right there.
from what i read on the caterham UK site, the 6 speed is now made in a "touring" model, so i expect that to have an overdrive. u should check for its availibilty stateside. also the sierra has no drainplug on the tranny. the caterham 6spd unit does afaik.
http://usa7s.com/aspnetforum/Default.aspx?g=posts&t=748
Al and my drive over the weekend. Al has the big brakes in a superlight. if he jammed on them there would be no way i slow down, so will eventuallly get them for the heavier SV. even outside of competition, the extra 1" diameter is a big plus with brake torque.