Front subframe with urethane and sway bar upgrade done

[M3M3]

looks familiar! i just finished same project..

[carlee]

Yup, what Paul said - urethane subframe and diff. mount will increase the in-car noise level an order of magnitude. If you're not willing to put up with that, you might want to reconsider. What are your overall goals/long-term plans? That should guide your decision process.

Looking for increased durability of those wear items? Better handling? What? There's a bazillion options for these cars depending on what you want to do. Daily driver with 1-2 driver's schools a year, 1-2 autocrosses, and you're just beginning driver's schools and the learning curve for that? IF the stock suspension is in good shape as are your street tires, probably best to leave it stock and take care of any needed maintenance items for the pre-event tech-inspection. As far as learning goes while maintaining larger safety margins, stock configuration vehicles are generally best for that. I think most would recommend that you do driver's schools basically stock until your skill and comfort level gets to the point that a specific thing becomes a substantially limiting factor.

For instance if you and your instructor jointly agree that you're now driving the car as best, optimally, and as fast as you can, but now you're exhausting the performance envelope of your street tires, and perhaps choosing a hi-performance or wider tire might be warranted.

After that, things open up a lot. First upgrade that will show a substantial difference: tire upgrade. R-compound tires are, generally speaking, probably a bit much to jump into as you do your first several driver's schools, as you'll learn more about how to manage your tires in less time with a greater safety margin than if you opt for some super-sticky mega-tire early on. Next fairly obvious and inexpensive things are stainless steel brake lines and higher performance brake-fluid, such as ATE Super-Blue. It starts to get to be a balance of choices - on-track safety vs. say, performance. At which point do you decide a roll-hoop and 5 or 6 point harnesses trump a suspension, handling, or power option?

If the track bug bites you, and you decide to do enough events that you progress to the advanced class levels (typically, A or B run groups in a 4 run group school), by the time you get to that level, a roll-bar is probably appropriate, despite it's compromising BMW's engineering & design to make the interior as safe as they knew how in case of a wreck or rollover.

But, if it's 1 or 2 driver's school a year for the forseeable future, maybe you opt to hold off on that path, and start going for handling.

Common E30 stuff - larger swaybars w/ urethane bushings (yes, the bushings may very well squeak nearly constantly, for years). More negative camber via offset strut mounts, lowering springs (w/ obvious ride-quality compromises), camber plates (or adjustable camber options), and rear trailing arm modifications, or bushing kits.

Hi performance or sport shocks, front or rear shocktower stress bars, offset control-arm bushings, beefier or reinforced rear shock mounts, and probably lastly consider the substantially stiffer urethane bushings throughout, but of course that consideration will come up as various typical suspension maintenance items come up. And then there's the various things that should be re-inforced or beefed up - motor mounts, swaybar mounting points, etc. And then you have to consider that all those nice, compliant rubber bushings you're replacing with something substantially stiffer won't be absorbing what it was before, and that force and energy has to go someplace, and will be transmitted instead to a steel piece which was never designed for that level of stress and will crack or suffer unless reinforced. (had a friend w/ his E30 M3 that had a cracked front subframe; however, its solid control arm bushings didn't have much option for force dispersement; I'll take the rubber M3 ones with their more frequent replacement interval and deflection over the option of a front-subframe failure). Of course, given the mileage on E30's these days, hardly anyone's going to go through a linear modification and upgrade path, more likely you need to make some decisions because why duplicate the labor expense for the same work down the road if you think you'd be inclined to do the modification anyway at some future point. If you drive the car all day every day, the stock rear subframe bushings are definitely quieter, and quite long-lived. Urethane bushings might not wear enough to require replacement if you owned the car for the next 20 years (I'm guessing, don't place a bet on that).

Best of luck regardless what you decide!