This bar was purchased during the Miata Games in Atlanta. The gentleman from Wiz advised that this little jewel would clear up some of the problems I was experiencing on the track and street by "tightening up" the front end. Figuring it was another sales pitch, decided that the approximate $40 would not be too big a loss if it didn't work.
Works fine! Thanks Wiz!
All needed hardware was complete, mounting holes lined up, and all nuts and bolts fit. Rolled the car up on ramps, got out the 17mm socket, open end 17mm wrench, and roll of tape. First noticed that the open end wrench or nut would not fit into the opening and could not use their suggestion of taping the nut and washer to the wrench. A few minutes with an old 17mm on bench grinder produced a thin wrench that fit fine. It was easier to reach over the top with fingers to place and hold the nut and washer while starting the bolt with my other hand. The problem was holding the bar in place at both ends while installing the nuts and bolts. Problem solved by rolling over the floor jack and using just enough pressure to hold the bar in place. Probably could have used the stock jack but that would be more work. Installation time was about 5 minutes, with another 10 minutes to modify the wrench. Others I spoke with that installed the Wiz and other type bars did not a problem with the wrench. Don't know if the 89/90 is unique to this or if just my car.
I ordered the front and rear braces from Wiz Performance. The prices of the two items combined to $82, plus shipping and handling, however I was only billed $75 (plus s&h) for the combination. Delivery took 3 weeks, as they were out of stock when I ordered.
Installation was simple. To install the front bar, I put the Miata on ramps, and was easily able to slide under and install the bar. Wiz offers the valuable hint of taping the nut and washer to the wrench until the bolt engages the nut. My only installation problem occurred when repeated attempts to engage the second nut failed. Just when I thought I had it, the bolt would drop out. After 15 minutes of struggling with this, I dry-fitted the pieces and found that the nut was too large for the bolt! A quick trip to Hechinger's and all was well.
Installation of the rear bar requires that the rear wheels be off of the ground. I am wary of working under a car on jack stands, but the location of the attachment points is such that I could reach them from beside the car, not under it. Wiz suggests that you mark the camber plate and the frame so that you do not affect your alignment. I did so and had no problem returning the alignment to specification.
Instructions are good, but the orientation of the front bar is not explained. It is not symmetrical in cross-section and can be installed either way without interfering with the suspension. I chose to install it with the 'bulge' up to afford slightly more ground clearance. (I have since received e-mail from Holly at Wiz confirming this as the proper installation.) Total loss of ground clearance, by the way, is about an inch. The rear bar can only be installed one way, so no guesswork there. Tools required for the front bar: 17mm socket and torque wrench, 17mm (I used 9/16) box wrench, ramps or lift, and tape. Tools required for the rear bar: jack, jack stands (or lift), magic marker to mark camber, 17mm socket wrench, ratchet, 17mm box wrench, torque wrench. Had I been sent the proper size nut for the front bar, total installation time would have been less than an hour and a half.
The performance improvement with these bars is definitely noticeable, but not dramatic. Cornering seems better (I didn't think that possible). I perceive an ever-so-slight increase in effort required for my non-power steering, but I like that. There is definitely less cowl shake when I hit bumps. I took the Miata for a high-speed spin on the beltway, and the alignment seemed fine; no 65 mph shimmy.
In short, I think these bars offer the best benefit-cost ratio of any after-market item I have bought. Other suppliers offer similar bars that would no doubt be just as good or better; Brainstorm's appears more substantial in their ad. I wish I had done this a long time ago!