I'm looking for information on putting Bilstein's onto a 1989 Pontiac Sunbird GT. I know Mantapart used to sell them, and my understanding was that they modified the factory Macpherson strut to accept a bilstein shock, and I assume you can use an off-the-shelf shock for the rear. Obviously Mantapart went out of business and I've only recently been in a position where I can finally put some time and money into this car. I've owned it since I was in high school (so I've had it pushing 15 years now) and had a lot of fun with it for the few years I drove it, but eventually I put it up on the shelf with the intention of some day building it up. Over the years I've slowly acquired a wide variety of parts to upgrade nearly everything on the car and I'm getting ready to pull it back out of storage and start working on it. But I could never afford the bilstein setup from mantapart while they were still around, so that's where I'm hoping you guys can help out. I know nearly every nut and bolt on these j-bodies, and I'm pretty knowledgeable about cars in general, but I'm not well-versed in the technical aspects of suspensions at all. I know how they go together and that's about it. So if someone out there knows what Bilstein shocks I need to order, or what details/specs I need if I contact Bilstein directly to try and order something, (my understanding was that the Mantapart guy used off-the-shelf Bilsteins which were appropriate to the size, weight, handling characteristics of the car, etc, and then just modified them to fit the j-bodies). I know my way around tools and have a well-appointed machine shop at my disposal (dad is a precision machinist, tool-and-die maker and designer by trade and started his own shop several years ago, I've worked for him off and on since he started it and have been his CNC programmer/operator for awhile now) so no matter how difficult the job is, I'm not afraid to tackle it. I just need to know what needs to be done. I've looked at the how-to on V6Z24's website for adding yellow Koni's to a 2nd gen, and if that's all that's involved this job will be a breeze, but again, I need to know what Bilstein shocks I need, and whether there's any mods/work that needs to be done to install them on the rear as well. The end-goal for the suspension is Bilstein's all-around, with Eibach 1" lowering springs, ADDCO sway bars front and rear, and upper tower braces front and rear, replace all the other little bits with new MOOG parts, and Timken wheel bearings. Any help, info, insight, experiences, etc. will be very helpful. Also, if you know of existing threads already dealing with this, point me in the right direction, (I did search already, but didn't come up with anything other than people just talking about them, or 3rd gen stuff which wouldn't translate to a 1st or 2nd gen). Thank you in advance.

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IIRC, the Bilsteins used in that kit were of the "build you own strut" variety. You get what looks like an insert with a threaded body, and then weld your own spindle mount tabs on. There has only been one person I know of that ever used the Mantapart Bilstein kit, I saw the thing in person once, but now that car is long gone, so I couldn't even direct you to look for it. There is one other car I remember using Bilsteins, but they weren't from Mantapart, he did all the homework himself. If you're just looking for single adjustable, I think a better option for you is to use Konis, since the part numbers and how-to are already out there. If you were interested in having double adjustable dampers, you could easily cross reference the part numbers to Koni reds and have at it. If you are dead set on using Bilsteins, all you really need to do is buy one Koni insert to pull measurements off, then call Bilstein, give them the measurements, give them relevant weight, etc, and they should be able to hook you up.

If you don't already have a set of Eibachs, you aren't going to get one, since they've been discontinued for years now. Your next choice is the Canuck 1.7" springs.
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So... the bilsteins are going to be next to impossible, and the eibachs will be impossible. That figures. I'll at least take a stab at cross-referencing the koni's to some bilsteins, if I have any luck I'll post, but that probably won't be for awhile. As for the eibachs, I did find a few sites that list them as being in stock, but who knows whether they actually do. I suppose I can try ordering them and see what happens. If anyone else knows anything feel free to chime in.

I know most of the places that list them as in stock don't actually have them. Over the last year or two plenty of people have tried to order them, paid, and then got the notice they weren't in stock and got refunded. They even pop up on ebay, but with the same results.
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