Minor driveability issue-smoothness

I have a few little nagging issues that culminate in the car being a pain to drive around town. The first I believe is caused by the muffler bypass pipes. At low rpm, say below 1500 or so, the motor won't bog but it won't smoothly accelerate like it did with stock mufflers. Additionally the throttle pedal (which via dura metric operates correctly with no dead spots) is extremely sensitive at the lowest range. For example, if I am rolling along at 2k Rpms in 1st, there is no way to smoothly roll on or off throttle without a huge jerk. This is a major issue because of all the traffic going to work on a military base. Trying to drive behind all the huge trucks of jacksonville, constantly tapping their brakes for stuff I can't see, is a pain. The slightest motions in the car, like hitting a bump or just the acceleration, will cause inadvertent pedal inputs that make the car very un smooth. The last item is the clutch. It sometimes seems to just clamp down on the engine all at once. I think sometimes this is aggravated by the ac compressor kicking on at a bad time. It's like the engine just instantly dies for an instant then goes again. I used to choke the car off occasionally before I uninstalled the helper spring. The clutch/flywheel are OE parts with around 30k miles. Before you jump to the conclusion that I suck at manual driving, I have been told by several that I am the smoothest they've driven with. I can do all the advanced stuff and even clutchlessly shifted for rally cross (not in the 911). Has anyone experienced these driving characteristics?

unfortunately some of the jerkiness can be caused by E-throttle, but also important to look for vacuum leaks in the intake system

Put your clutch helper spring back. Put your original mufflers back then we can talk.

One of the most impressive things about my 02 Boxster's engine is its tractability at low RPMs, in part due to the high compression ratio but also due to the VarioCam system. VarioCam valve timing is active at around 1500. This relies up an expected back pressure of the exhaust to properly function. Thus I would have to believe Hurdigurdiman's advice regarding (re)installing the factory exhaust is while stated a bit harsh is probably on the mark. For the clutch behavior I can tell you based on my experience with my Boxster a clutch fluid flush/bleed can work wonders on the clutch's action. A clutch that was grabbing and thus making it hard for me to effect the usual smooth take off from stop, and the hard to shift without some crunching no matter how deliberate I was in pushing the the clutch pedal down al the way, were both cured with a clutch (preceded by a brake) fluid flush and bleed operation. The one previous was around 2.5 years prior. And I too am smooth with the clutch. The Boxster's clutch is original and has as of now almost 282K miles on it and one doesn't get this life out of a clutch by being rough with it. Oh, I do not know what role the removal of the helper spring plays but I again would have to side with Hurdigurdiman on this. For the throttle action I'd try a recalibrate operation of the e-Gas before I delved too much further into the e-Gas system. With the ignition key off turn the key to the on position. Do not start, even crank, the engine. Avoid touching the gas pedal. Leave the key on 60 seconds. After turn the key off and leave it off at least 10 seconds. The next time the engine is started the recalibration is complete.

You can also take the pedal assy out, take it apart and clean & lube it to make it much smoother. There are some threads on this forum about that.