If you're going to pay to have it done, don't use anyone but a Porsche mechanic. Preferably an independent shop with Porsche trained specialists. My mechanic for the Dodge will not even look at my Porsches because he says they are a different beast, and he's right.
As for the lightweight flywheel, it's a great thing if you know what you're getting into. Your starts will be quick, but the stress on the drive shaft is increased so you need a clutch plate with springs to absorb some of the stress the dual mass flywheel used to absorb. Also, when you're driving slowly in traffic, you will jerk around a good bit so be ready for it. Personally, after researching the lightweights, I'd only look at flywheel replacement if the old one is bad.
Good luck!
