if you are DIY'ing, with realistic DIY equipment (not a heavy car person DIY garage with a press and lots of space to leave the car in the air, maybe a second set of hands etc), I think 2 piece is the way to go.
Many people with the Aluminum ones have said that they don't really add any NVH at all, although there isn't any long term notes on suspension longevity, but I don't think they would effect that either. But you would need to press them in from the top, which means full subframe removal, etc. Like I said, if you don't have a press or enough area/time to go this far, 2 piece should be the happy medium.
Honestly, I've had the 2 piece whiteline RSFB in for a a few years. I could have just forgotten what the car felt like before the RSFB replacement, but I felt that the rear arm replacement with the M arms (
https://www.ecstuning.com/b-trw-part...3322283547kt4/ ) did a lot to help settle the rear jumpiness even more than the RSFB replacement, although I guess it could just be the combo of the two.