When I got mine, (5speed), the cold shifting wasn’t great. Changed with Porsche oil at 60 000 miles. No improvement with shift quality when cold. No problems when warm. Still happy in knowing the oil is fresh.
I used Royal Purple syn oil as its supposed to be OK for the brass synchros- shifts OK as fluid that came out looked brand new :/ about 8k on the RP and no issues
Make sure you follow the factory fill instructions, it is not fill until it overflows.
My 01 has been running Royal Purple for about 50K miles, shifts well hot or cold. In the cold the Porsche brand was a little more stiff at sub zero WI temps.
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1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.