Wider front tires

[clickman]

2001 base with stock 17" wheels. I need new tires and some have recommended moving from the stock 205/50R17 to the wider 225/45R17 in order to reduce understeer. I'd like to do that but:

1. Are there any negatives?
2. Are spacers required?
3. Should the air pressure be adjusted from the stock tire Porsche spec of 29 psi?

Thanks