JPR also had a great post on coolant somewhere...
From what I know, it's OE or G-05, but just yesterday saw a BMW coolant bottle posted here that had a typo...said Volvo in one instruction and BMW in another...so some Volvo coolant would work too, I suppose.
It should be a $25 investment every few years. I have to do mine...will plan on it in the spring when I put in a new WP just to be safe(r).
Upcoming NYC dates: Jan 8 and 27. See Facebook for other shows and PM me if you can make one...love to see you there!
Mangofy your E46!