i am always looking for alternative wheels for track tyres and as spare. the odd sizes and very odd PCD make this task almost impossible, therefore well expensive, originals from lotus or speedlines, both pants down expensive.
whilst trawling red motorsports website, they are very sucessful in the german lotus cup, I see they offer a nice set of wheels for the S1.
The Komotec website lists the weight of Speedline Mags as 8.2kg fronts and 8.9kg rears. That sounds rather heavy to me, when the stock ones are 8.5kg fronts and 11.2kg rears.