Because there's absolutely NO reason to. There isn't even an upgraded set of turbos that one can buy that could even begin to utilize the extra flow the cams would provide. The stock turbos can be easily max'ed on the stock cams.
'15 AW/SO F80 M3 6MT: IND cosmetic package, Gloss black grill surrounds, Macht schnell 15mm spacers all around, 3M crystalline
'07 997 TT 6MT, Arctic Silver/Sea Blue: FBO, stock turbos, Cobb/PTF custom 93/E85, H&R, 19" BBS CH-R in widebody fitment. 6.700 60-130, 93 octane