244, 160K miles. Yesterday I replaced the rear coils with a set from another car - a set I knew to be newer. I also rotated the tires (stock-size radials). And changed the oil and replaced the front pads - the last 2 should be irrelevant.

Driving it today I found the car wobbly - a twitch of the steering wheel makes the car lean and sway dramatically. Perhaps like strong oversteer; or a broken tracking bar; or a low tire. At 1st I thought I'd left something loose but I checked and no.

2 possibilities I can think of: 1) the replacement springs are weak and allowing the rear of the car to sway. 2) It needs an alignment and while the pre-rotation front tires were used to it, the back tires (now on the front) aren't and so an oversteer condition that I hadn't noticed before is exacerbated.

Anyone have anything like this happen? Any ideas - am I missing something? The shocks are OK - nothing special but not old. Tires are some off brand. Pressure is correct. But, again, the car was fine before yesterday.

I'm going to re-replace the rear coils tomorrow and see what happens. If it's the same I'll re-rotate the tires.

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240s: 2 drivers and some parts cars