softer suspension

[blue2000s]

I'd suspect the wheels and tires as noted above. Sidewall stiffness will make a big difference in the way your car rides and handles. What wheels do you have? How do they compare to your friend's car? Some tires are made for handling, some are for ride. You might consider a more ride-oriented tire. In my experience, both wheel diameter and sidewall design can make a very noticeable difference in ride.

Also as noted, worn out, sagging springs will tend to bottom the suspension more easily. Is your car riding low on stock springs? Do you feel the harshness only over larger bumps or are small bumps also a problem? If you are using lowering springs on stock length struts, you can also run into bottoming issues.

General ride discomfort is more likely to be your tires. Hard hits over only large bumps could very well be bottoming out of the suspension and you need to replace your springs. Stock springs in good shape should not allow the car to bottom out under normal driving. Replacing the springs with a new set of stock parts is cheaper than going the coil-over route and still gives you a nice-handling street car.

[FTD]

Increasing your acceleration through turns and making stronger 'right angle' turns instead arced or 'semi-circle' turns will greatly improve your experience and reduce the 'bumpy' sensation. If you take turns at a legal speed and you start to feel the pull of centrifugal force, then tires or suspension may need to be addressed.

Just my off the wall $.02

[tommy986]

Start with something simple. Check that your tire pressure is correct to Porsche recomendations. Tire installers tend to over inflate.