I'm running the Disco steel rims on my series 3 and they are a nice rim. The steel used to make the rims is much thicker than the standard series rim, actually, they are as thick as the wolf rims.
The disco rims have a greater off set that the series rims, therefore giving a wider foot print on the road. This in turn gives a more stable ride. If you are deciding to go to a super wide tire ie: 12.5 x 33's, you'll have body contact, but with 235's I have no problems.
Going with or without tubes, is no more than a personal choice in my eyes. But with that said, I wouldn't use tubes, if you for example get any dirt caught in between the tube and the tire, it will wear a hole in the tube, making them a waste of money.
The disco rims are a quality rim, even using the tallish 235's, I've never broke a bead or got a puncture.....knock on wood
Going tubeless with either rim, you'll do fine M8.
Cheers,
Tuko.