Last saturday a friend and I replaced my left trailing arm due to the fact that it was bent. The install was fairly straight forward, and we were able to get the car together in one piece and running. However, because I messed with the toe compensator arm, I got a pretty bad vibration in the steering wheel, which I thought an alignment would fix.

Yesterday I had new tires mounted and balanced, and took the car in for an alignment this morning. Just got it back (they said my numbers are perectly within spec), and I still have pretty bad steering wheel vibration (not as bad as before but it is definitely there), from 70 - 85 mph. Anything before and after is absolutely fine, but during that particular interval the steering wheel starts shaking.

All suspension components seem tight and intact, nothing is loose. The tires are brand new, and were mounted yesterday - I checked and I am not missing any weights.

Can someone please tell me what else could potentially be causing this??? I am completely baffled, and it is extremely uncomfortable to drive around like this (especially with a commute like mine). Any ideas are greatly appreciated!

If it matters, the car is 2000 civic ex w/ rear disc brake conversion, 15" rota slipstreams with Falken Azeni Sports, GC + Koni Yellows, progress auto camber kit.