Problem fixed:
MAF sensor needed either a clean/replacement. I opted to just have it replaced. I was skeptical about it being the MAF because I haven't read anywhere on how it disrupts cold starts. I always thought sluggish, rough drives when engine at operating temperature were possibly symptoms of a faulty MAF (fault codes of course too, but I had no pending or present codes).
It has certainly been a journey, since this problem has persisted for past 6 months and finally, I can say, this car running optimally. Though, 2.5L, is seriously underpowered. Sigh...just took out for a drive. It sounds good but feels slow. I think it's because I just watched this video:
YouTube - Porsche Boxster S PDK vs Porsche 911 Carrera 2S Convertible (997 Mk I) 6-speed x 2 + stabilized
Gosh the new Boxster models are fast, but I feel lucky just driving a Porsche!