I wouldn't waste my money on an oil separator. That little bit of oil going back into the intake won't hurt anything.
I ran one on my TVS car and didnt empty it for 5 or 6k miles. car barely had a teaspoon of oil in the separator. I would say not really needed per se' however its a nice precaution IMO.
As far as the the question at hand i would do exhaust. I never had issues shifting the 12 with just a JHR bracket and line. This new shifter feels pretty good so I am in no rush to replace that either. I have had 0 issues with 7k rpm shifts so far.
I asked my tuner if I needed a oil separator since it seems like everyone is buying them. I have a blower & make 600whp. He told me he never runs one & they're a waste. The little bit of oil doesn't hurt anything.
IMO... It's called marketing. Make a product to sell & make a profit. As long as they are selling it doesn't really matter how much benefit there is...
I agree it's a marketing thing. They show you the oil collecting in the catch can and interpret that as something bad. That small amount of oil compared to the amount of air/fuel the engine is using is nothing and it certainly isn't bad for the engine.
I run breathers on mine and a gt500 pcv valve on passenger side. I just do it because I like the way it looks
Anyone else share this mans same opinion? I feel if it wasn't needed they would have never made one. But that's just me