I did the same, in the end the 335i felt too big and needed £X spending on it to get it just where the 135i is from the factory.
135i = Drivers Car
335i = Somewhere between drivers car and luxury car (but it's neither)
E46 335i = That's a car I wish they made
I've no experience with the BMW PPK but it's not 350bhp that's for sure. PPK1 was 320bhp & PPK2 is 330bhp...same as US 135is & new F20 M135i.
I skipped the PPk and headed right for Cobb which frankly turns an already good car into something insane.