turbo seals do not cause misfires. Plugs could be fouled from all the raw fuel the injectors were dropping. Keep in mind your using used parts that were recalled for leaking and causing misfires on start up.
If it were turbo seals you would know it. Your turbos are fine.
BMW master tech
2010 E92 335i 6-speed 25k miles. - For sale.
1989 E30 325i coupe 5-speed DD