The original Porsche 996 came with a 3.4-litre engine that developed 300bhp at 6800rpm and 350Nm at 4600rpm. Then, in 2001, came the so-called facelifted 996 with its 320bhp (at 6800rpm) engine that developed 370Nm at 4250rpm.
The 3.4-litre is a sweet, free-revving and arguable is the more fun, as you have to work the gears more to get the best from it. The 3.6, in contrast, has noticeable more mid-range torque so you can afford to be a bit more lazy with it. And it’s that extra torque that makes the later cars feel quite different; more refined but at the expense of the zing of the 3.4. They’re both good engines but each with their own character.
Internet forums would have you believe that the earlier 3.4s are more troublesome, but I’m not convinced. It’s essentially the same engine and, in both cases, there have been small numbers of issues with IMS failure. However, generally, IMS fail at low mileage and there aren’t many low mileage 996s left, of any age. RMS leaks are inevitable on any 996 or 997 and something you can generally live with.
My advice, then, is to buy on condition – a good well-maintained 3.4 can be a better buy than a neglected 3.6.