Fluids, lubricants etc

Good Afternoon,

now that I've got me a nice and tidy series 3, I thought about changing the oil in the gearbox, diffs and engine. As I'm in Frankfurt now, and stuck here for a while, I've found these:
"DOT 4 LV" by Pentosin
"20W-50 Super Dynamic" by Pennasol
"SAE 90 GL-4" by Pentosin
Blue antifreeze by Pentosin

Anyone has experience with Pentosin? Are they any good?
I know I can't take Dot 5 brake fluid, and I know that the brake fluid in her is dot 4. Should I consider something else?
Is there difference between cheap and expensive motor oil, as long as it's 20W50 (Which is in the engine at the moment)?
About the gearbox oil: I've found that putting in GL5 is evil, and SAE90 means EP90 doesnt it?

The other option is to order it from Blighty, but the shipping would be bloody expensive with 1+10+10+6L...

Thanks in advance.
Phil

PS the shop I've been looking at is www.motor-oel-guenstig.de

I think you'll be fine get on with it, pentosin I've never heard of, however I'm sure its a whole lot better than the black turgid filth thats probably been in your series for years.

Good oil and cheap oil usually use the same base stock, allthough some cheapies use recycled stuff, its the additive pack thats diffo, oil contains additives like antioxidants, thermal stabilisers, viscosity controllers etc, these are usually more effective and last longer in higher quality stuff.

Not many of these were around when series landys were made, however reasonable oil is a good idea.
I wouldnt reccomend putting synthetic, or semi synthetic in a series.

Thanks for the answer dr pepper. I'll see what comes out of her this weekend.

So, as my oils are arriving in time for the weekend (I hope), I thought I'll write how they do in here. If some of you have experience with different oils for series lr just put em on here and I'll make a list. Dont want to go into the gearbox just because of bad oil...
Cheers,
Phil