Not much of an update, but just a quick post about the experience that I had with the 18" M parallels fitted. So as I previously mentioned, I bought a set of staggered E39 18" M parallels, which are known as style 37, and here are some details about them.
Front wheels: 18x8J ET20 (74mm centre bore), BMW part number: 36 11 2 229 635
Rear wheels: 18x9J ET24 (74mm centre bore), BMW part number: 36 11 2 229 640
I put the size of the centre bore above for a reason, because you will need hub rings if you are planning to fit any E39 wheels to your E34. As you may already know, the hub size of the E34 is 72.5mm, so just a bit smaller than what's on the E39 and that's why you'll need the rings, because the wheels may fit fine, but you'll definitely get vibrations on high speeds, as they won't be perfectly flush with the hub without the centering rings.
Also keep in that mind, that E38 7 Series and the E31 8 Series had these wheels from factory as well, but with different offsets and rear wheels being 9.5J. If you get a set from these models, then you'll have to check the fitment yourself, but the good news are that you won't need hub rings, as both the E38 and the E31 have a 72.5mm hub, same as the E34.
When I bought the wheels they had some random budget tyres on them with the sizes not suitable for an E34, so I bought a set of 245/40/18, two being Bridgestone Potenza (front) and two Pirelli P Zero (rear). There are many different opinions on tyre sizes, but I decided not to experiment and just go with the size that was fitted to all facelifted M5's from factory, which is exactly what I put on. I also fully refurbished the wheels inside/out before putting the tyres on.
See the BMW M Registry for the reference: http://www.bmwmregistry.com/model_faq.php?id=12
The 245's on the front fit so closely to the shock that first I even thought they were rubbing, but after some checks and test drives, it turned out to be just my imagination...These wheels with these tyres fit 100% to an E34 with stock suspension, and it will probably be fine with some minor lowering as well.
Now you would think I'd be over the moon with the wheels and take tons of pictures with them on the car, but to be honest I was quite disappointed with them, because putting 18" wheels after having the original 15's felt like I completely ruined the ride. Yes, they definitely made the car more stable and flat around the corners, but the steering became heavy, the ride was very hard and after driving with them for a few weeks, I decided they are not my cup of tea.....So now I'm going to sell them and will probably go for something smaller next, most likely 17" and ideally M Throwing Stars (style 21), if I manage to find a set.
In the meantime, after doing some research on the driver's side wiper arm, which has the annoying reverse-hook, I found out that the driver's side wiper arm from an E36 is a direct fit to an E34, assuming you don't have the high-pressure wiper rack fitted. So I popped down to my local scrapyard and bought an E36 driver's side wiper arm for 10 quid, which as expected, fitted 100% - just make sure you also get the rubber plug from the E36 to cover the nut that secures the arm to the rack.
Now with both wiper arms being "normal", I upgraded my wipers to Bosch aero blades, which are a MASSIVE improvement compared to regular blades, and I would highly recommend them. They are quieter, clean better and are cheaper as well, because you can easily get a set for 20 quid from eBay, while E34-specific normal blades are at least 30-40 pounds. Aero's will probably last longer too:
And that's it really...Have to admit, E34s look great with M Parallels, but I just couldn't live with that ride. There's a chance that I would possibly get used to it after a while, but I really felt that 18's on an E34 are more about looks, rather than function - that's just my opinion anyway. I guess I'll have to wait until I get 17's to be able to compare, but I'm pretty confident they will be a perfect choice - not too big, not too small and with an acceptable ride/handling.
Apart from that, I'm planning to get a Bilstein B12 Pro Kit soon, along with top mounts all around, as well as bump stops, dust covers and some other bits. Will keep you updated as I go along.
Thanks for following.