Hey up. Gonna chime in just because it passes the time until I get mine haha.
I'm in a B9 S4 Avant coming from the B8.5 S4 Avant. New chassis is much lighter and has more exhaust character/cracking interior etc but like you, it's time to get into an RS and I've always loved the B8.
I did look at the RS3 PFL and that 5 pot and exhaust are other worldly. Insanely loud and bags of character. It'd even be better on the roads I drive being in the hills BUT, it's just too small and the interior just feels a bit...can't put me finger on it. Not a reason not to buy it though. Great engine. You'd be giving up a lot of boot space mind you.
So I'm going for/holding out for a Sepang Limited Edition RS4 Avant. 2015. There is a bit of weight in the nose from my limited time with one but I wasn't driving it on full chuff. For me, it's just an iconic car with a timeless look and one of the best engines ever built. More grown up than the RS3 but still with loads of umph. I'm going Cat back Miltek when I do get it. So aggressive.
@DeanoC is the RS4 ownership guru and there are some great guys on here that know what faults to look out for.
Great dilemma you've got anyway

Enjoy.
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