I used the FCP kit with the built in alignment tool. Zero issues so far after over a year.

 

There are 2 versions of this repair;
1. seal only, where you need to remove old one and press the new one into the housing
2. seal with housing, pre-pressed.

First requires some finesse to press it in without messing it up and second requires removal of the oil pan. If you're doing the oil pan gasket, it's easier going with this option.

If you remove the seal with housing, make sure you use a torque wrench as it's easy to ruin the soft aluminum threads. Thread sealant (not thread lock) is required for 2 of the bolts as their end comes in contact with oil in the oil pan.

 

OP, is the RMS leaking? If not, I wouldn’t worry about it. Early M54 engines had a poorly make RMS. They usually weeped oil at 100k miles. Later engines (2003 I think) have a much better RMS. So if it’s not leaking/weeping I wouldn’t worry about it.

 

RealOEM lists the current PN as 11141438274, which superseded PNs 11141433897 and 11141744158, so it's possible that the new PN overcomes the failings of the initial part. I had the -8274 installed in my car last year, and have had no leaking problems.

 

My car from 2001 325TI rms was still leak free after 300000 km. But I have replacrd by OEM one at 300000 km. And don't forget to uy new metal gasket.

 

If it’s not leaking, I would not replace it.

Viton is great, but the RMS seal does not dry out like the oil filter housing gasket, valve cover gasket, or the vanos seals.

if you do replace the rms, follow Paraklas’s advice. Particularly on thread sealant. Many RMS jobs leak because they skip the sealant.

when I replace an RMS, I buy a corteco (or similar quality) non-Viton seal and tap it into my original alum housing.