Redline makes extremely good lubricants, and is a step up from Royal Purple. I use their D4 ATF in my 328Ci's 6spd Manual (swapped from '06 330Ci ZHP), 325i's 5spd Manual, and 740i's 5spd Auto. I use their 75w90 in the differentials for the latter two (328Ci has a Quaife LSD so I use their fluid).
I also use their oil in all 3 of the Bimmers, around every third oil change is RL with the other two fills being RP, and use RL in the 328Ci for track use most of the time and RP for street use. Due to a combination of high compression and over 16psi boost, I change the oil frequently as it is a shared system with the supercharger.
The results, well, speak for themselves... Since using these two exclusively, all 3 cars have been completely free of sludge/varnish, and they all started out with more sludge than one might expect, due to long OCIs from the POs. When I tore down my 328's engine for all the upgraded internals prior to the SC install, everything was spotless, and according to my friend (BMW Master Technician who now owns his own shop) who helped, it was the cleanest he has ever seen in over 20yrs of working for BMW. He also said that the wear levels were significantly lower than expected, and now he stocks both RP and RL at his shop and I let him borrow one each of my OEM Pistons, Connecting Rods, Camshafts, and Intake and Exhaust Valves which are displayed by the RP and RL products. They each sit next to an OEM part from the same engine with only a bit more mileage but that had been on BMW Syn and M1 Syn oil their entire used life. The difference is amazing, to me at least.
I say, from experience (although different than yours), to use RP HPS oil or if you can find SM-rated RP (has "with Synerlac" across top of bottle front label) then get that.
Redline D4 ATF and their gear oil should be a great and worthwhile change. They are not terribly expensive, considering the long change intervals, and perform amazing; you may even be able to feel it, or may not.