M30 cranks hard but catches quick?

[Armageddon535]

It catches quickly and never fails to start, but it feels like my 535 cranks on the hard side when warm. It isn't really a problem yet, just embarrassing when I've got a passenger and turning the key produces a loud, almost shaky, clanking start.

Thoughts? Distributor cap? Starter? Coils?

Replaced injectors, O2 sensor, alternator and battery within last month.

[thespeedfactory]

What plugs are you using and how old?

[Armageddon535]

Bosh premiums, installed about 2 months ago, forgot to include that...

[thespeedfactory]

I would check all the usual suspects first...rotor, cap, wires. Check the resistance of each plug wire. You might have one or two bad ones. Should be a thread about that somewhere on the forum. If not, I know the info is on bimmerboard.com

TJ