I currently have Bilstein HDs and M3 springs. I plan on having 22mmF/19mmR Suspension Techniques sway bars in the car soon. Is there much additional advantage for adding a front strut bar as well? If so, what are your favorite manufacturers? I found a Racing Dynamics 1/2" thick bar on ebay for $50. This would not necessarily be for the track or autoX, mostly just spirited everyday driving.
Strut bars support the unibody, providing strength & reinforcement, alleviating some stress and flex on the shocktowers, as well as sharpening steering response. I have a BavAuto bar on the front, and a Hartge bar on the rear. I think the Ireland engineering site (maybe Turner? or Pelican Parts perhaps...) has a discussion that there may have been some minor difference in different E30 chassis production, as there were enough incidences of some strut bars fitting perfectly, and others not. I got my BavAuto one before that came up, and had to modify it to make it fit mine (production date May, '87). I kind of think they're a no-brainer if you're willing to do it. E30 chassis are stronger than the E21, but my lowered, Bilstein sport-suspensioned 320i eventually suffered cracked rear shock towers, and I had to have one custom fabbed after that was repaired. If you want to preserve your E30 for perpetuity, they offer a handling and performance improvement, as well as an easy preventative measure against overstressing the shocktowers. I don't know if there's been anything conclusive determined whether a one-piece strut bar is superior in functionality to one that bolts in to shocktower-mounted brackets. There are obviously a variety of offerings out there.
After a bit of sniffing around, it seemed to me that they are worthwhile as a preventative measure if you flog the car. I put one on my 318i which I autocross (and a bit of track); but have decided not to bother on my 325ic which is now on cruiser car duty (although driven hard at times). (Rear bar I hadn't heard anything problems before.) Probably strut braces is an item where bigger is better. The biggest honkin' strut brace I could fine was the Sparco brace ($120). Its a big red thing, so not exactly automotive bling, but is a great place to stick all the stickers you get with brake pads, swaybars etc (I even put the Sparco sticker on mine). http://bmwcca.org/forum/showthread.php?t=4120
