I had my xreas removed and bilsteins installed as well as spidertrax, now whenever hit 55mph the steering wheel shakes. It ends around 75mph. Is this an alignment problem? The shop says they performed one. What could this be due to? Thanks.
Make sure the spidertrax and wheels are torqued properly. If the shake still exists, it's most likely a balance issue. With the tires pushed further out by the spacers, things like an out of balance tire/wheel are more noticeable. It's likely it was out of balance before, but only now made apparent with the spacers. I had the same issue, although it is odd that it ends around 75 mph as mine was constant above 50.
Yeah, it should be an issue with either spacers, tire balance or alignment. I would check each them one at a time until it goes away. If they did an alignment they should be able to give you the report. While you have the wheels off checking the torque on the spacers you could rotate the tires to see if that changes anything. If the vibration persists but seems to be coming from a different corner then it's probably a tire out of balance.