I work at the dealership in Medicine Hat and had one of these last year that had the same prob. Did it from new, his dealer could not sort it out either. Start up easy, run for 30 secs to a minute and bam, drop a cylinder. Fouled plug. It would alternate cylinders also. After it warmed up it was fine for the day. I took my wife's 11 pro to work and switched everything under the sun, one piece at a time and nothing helped. New injectors twice, new stator. Last resort i tore the top end off, the rings never did seat and the cyls were glazed like glass. The bottom end had carbon deposits in it and was quite black in places. Deglazed the block, new pistons and rings. He took on a couple trips after that,(no snow where he was from) put 300 miles on it and never killed a plug. There has been a few cases where injectors fixed the prob, new stator fixed the prob. I still think they ended up with rings on some 11's that were just way to hard and would polish the cyls like glass. With the rings not sealing when the engine was cold they would just recycle exhaust gas back into the case. Rich condition.
White smoke would indicate a coolant leak...which would foul a plug. Maybe some of these sleds had bad top end o-rings or the head either wasn't perfectly flat or not tourqued properly. Cold starts is when you would notice it for sure. Once everything is warmed up and expanded then a coolant leak may stop.
