Rancilio Ergonomic Bottomless Porta Filter Tight and Leaking

Many report that the bottomless portafilter from Rancilio is very tight, can't be locked in very well, hard to insert, cannot rotate very far or is leaking.
This is a known issue and has been discussed widely. Ironically, it seams the worst compatibility is using the ergonomic bottomless portafilter on the Rancilio Sivia.
- You will have to tighten the portafilter harder to the right in order to stop the leak. Especially if your gasket/machine is new. After a while, it'll be easier as the gaskets get worn in.
- The VST baskets tend to fit a bit better creating a better seal between the filter basket, portafilter and group gasket.
Read the following blogs and reviews:
http://coffeegeek.com/forums/espresso/machinemods/447167
http://www.toomuchcoffee.com/index.php?name=PNphpBB2&file=viewtopic&t=8461