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Start with the basics. You list a lot of potential weak points, but start with what absolutely should be done, then drive the car a bit and see what still bothers you. First things to do are the rear swaybar and the steering clamp and brace.
The rear swaybar will not reduce chassis flex. It does not connect to the subframe at all, but only to the suspension. What the swaybar does is reduce body roll. As a result, it will also keep weight balanced better, which will reduce wheelspin. Put on the new swaybar and drive it for a while before you decide whether you want to replace springs and/or shocks.
As for which swaybar to use, performance-wise, I'd have trouble imagining that there's any difference between them (unless you get a 19mm; see below). From what I've read here, they're all decently manufactured. They'll all be miles above the stock bar. The Abbott and MP bars are 22mm; Genuine offers a 22mm and can special order a 19mm. For a Viggen, there's been some discussion that the 19mm rear swaybar might be better than the 22, because the suspension is already so stiff that the 22mm swaybar will just make the car oversteer too much. Search the forum a bit, and maybe ask on the performance bb. Ask Nick at Genuine; he's done a lot of mods to his Viggen, and he sells both sizes, so he might have some good insight.
The steering clamp and brace will take some of the mush out of the steering. This will reduce torque steer. It will also mean a more direct translation of steering input to the car's direction. This may reduce your perception of chassis flex. There have been long discussions here about which model is best. Looking at the designs, the MP one will be the least stiff, but probably more than stiff enough (ie, you probably couldn't tell the difference while driving). It's also designed to minimize vibration to the cabin, and it's the cheapest. Might be the best choice for a daily driver, especially with value in mind.
Let me just go through your points in order to clarify things:
(1) torque steer: It will always be there, but you can minimize its effects by reducing body roll (swaybar) and steering mush (clamp and brace). Further reduction could be achieved by stiffening the chassis with strut braces or subframe braces.
(2) Chassis flex: You'll need a subframe brace or strut brace to fix this, but better steering (clamp and brace) may make it less noticeable. Do the clamp and brace first, then re-evaluate. Also, your mention of the intentionally soft viggen strut bar...I'm not sure if this is accurate. Were you maybe reading about getting a softer rear swaybar on the Viggen, as I described above?
(3) Body roll: Put in a new swaybar. The Viggen shocks and springs are already pretty stiff. If you're still not satisfied after the swaybar, then look at shocks and springs.
(4) Shifting: Check what type of transmission fluid you have. Most people (myself included) report that upgrading to MTF0063 (if you don't already have it) makes a big improvement in the smoothness of shifter motion. Your car did not come stock with this fluid (stock on '01 and later), but there should be a sticker in the engine bay that indicates whether it's already been changed out. MTF0063 cannot be mixed with other fluids, so you must flush and fill three times to make the switch. The procedure is on Genuine Saab's service info page.
(5) Wheelspin: reduce the body roll and steering slop first. Make sure you have good sticky tires. Then look at chassis flex. You have to keep the wheels on the ground solidly to keep them from spinning. LSDs are beyond what most of us would consider, but check out the performance bb here; it has been done, and I've seen some good reports on the Quaifes.
Welcome to the family. I'm sure you'll continue to enjoy your Viggen, for its performance, its utility, the comfort of those excellent seats, and the peace of mind you get from its safety engineering.
Matt
'99 base
posted by 65.106.18...
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