Is it possible to just order the 02 bixenons from the dealer, and install those, or is the PP ones the only way that this can be done? (price aside)

Check with the guys at www.MBNZ.org there has been a long discussion on that retrofit. I believe PP does the adapter installation so that you only have to plug it in. Otherwise I believe it is the same lamp...
hope this helps

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'02 C240
'00 LR Discovery
'72 280SE
'67 280SL

---past---

'79 280E sold (RIP)
'86 300E sold
'87 300SDL sold
'90 Laforza sold
'95 320SE sold
'98 ML 320 (sold)