Shaking steering wheel at high speed

[amrenane2010]

I just bought a 2004 Boxster. It drives extremely well and overall I'm very happy with it. Two things I've noticed:
1) Driving with the top down and exceeding speed of approx 70 miles, the steering wheels starts to shake considerably. Is this just a basic alignment/balancing thing or is it mechanically caused?
2) When I signal either left or right, the blinker stops after 1-2 times and doesn't signal anymore. Furthermore, when trying to turn on the headlights, I need to turn it on/off a couple of times to actually turn on the light.

Any advice / help out there?

Thanks