I'm thinking about installing a rollcage in my E36...
The main purpose of roll cages is to protect the passengers in the event of crashing and/or rolling. But there is one other crutial bonus to rollcages: They stiffen up your car's body, thus improve handling. A lot of people put strut braces on their cars, and rollcage could be considered an 'ultimate strut brace'.
There is also a negative side to the story - Cages are made from steel tubing. And steel tubing is quite heavy. You would have to spend some extra time and effort on your 'car-diet' plan to compensate for the cage if you put it in.
Of course, you can choose from a wide variety of cages. Proffesional multi-point weld-in cages are absolutley the best. But for an amateur, a half-cage would do just fine. (Half-Cage: Rear half of the rollcage, consisting of a roll-bar and two attachements that go to the rear struts)
The danger in this buisness is lack of quality. We all know that roll-cages can be easily made at home. One would think that we need some steel tubes, an angle grinder and a welder... But that's far from the truth. Please, for your own safety, DON'T MAKE YOUR OWN CAGE! (That is, if you're not an expert fabricator and welder!) Be sure that your cage is from high-quality steel. Make sure that the person installing you cage has a welder's certificate. And check out the angles where the tubes are bent - first of all - the tubes must be bent - no welded angles allowed here! And the bends must be smooth, and not crushed! And one other tip - there's no point in installing a cage in a old rust-bucket! that's why I decided to buy a new shell for my Beemer! :)
The conclusion would be this:
Buy the best BRAND NAME rollcage you can afford. Be sure it was designed for your model, and go to a certified expert to install it. And think twice before installation - do you really need it? Think about pro's and con's. After all, it's your ride!
And, here are some pictures: (hard to find)Found here: