For the record I have a 150 that I built in 2010 and has now done 24,000 miles. The original mapping was a problem. When new the car wouldn't start at all. Caterham re-mapped it and it ran rough. Subsequently in the first 6 months they re-mapped twice more and each was a vast improvement. The final version has been brilliant ever since. The lambda seems to have a life of about 10,000 miles. When they fails, engine running becomes rough and hesitant, particularly at low and medium revs. The fault doesn't appear in the first 90 secs from start up as the ECU isolates the lambda for that period. To get home you can unplug the lambda and the problem goes away, but don't leave it like that as you will damage the cat. I have also found the wiring to the lambda to be fragile and open to being damaged by rubbing on the underside of the cill. I have resolved that problem by enclosing the wiring in split 1/4 inch rubber tubing and sealing wires and plug with insulating tape. The 150 seems to be hard on plugs. I had a plug failure that produced a misfire that I hastily, and wrongly diagnosed as lambda failure. The symptoms are similar so I suggest that you keep a good set of used plugs and try these before investing in a new lambda. Finally I have to say my 150 is an absolute joy to drive. It has loads of power and torque, and the sound track with over-run pops and bangs is just amazing. It has taken me and 'er on many a long tour inc France, Switzerland, Spain, IOM and just recently, Ireland. The lambda is the only item that occasionally fails, so I carry a spare. It seems a shame that Caterham didn't persist with the 159, but the few that exist must surely be destined to be collectable rarities. Peter