Useful extras 997 CS

Hello friends, I’m about to order a 997 S. I’ve also put together the extras so far. What can’t be missed, what can’t be retrofitted? Of course, it’s best to bark everything, but there must be a break somewhere. The following extras I’ve got in mind: 997 CS, basalt black full-heeled black sports exhaust system Carrera Sport Rad Parkassitstent sliding roof dials black seat heating hub Navi phone module (the S has Xenon and PASM as standard) What recommend is the sound system indispensable? Does the sliding roof make sense or does it only take away interior height … I ask for critical remarks. From my other thread I understand that you can expect a discount of about 6-7%. Then Porsche seems to be doing much better at the moment than Mercedes in the sports car segment. They are currently giving significantly higher discounts. Thank you.