The earportz are a definite upgrade from the stock Westone tips. Was using the large grey oval silicone tips before getting the earportz and upon hearing the earportz for the first time I didn't like them so I went back to the oval tips. But then I remembered when I first heard the Westone 4's I wasn't blown away and gave it time so I decided to give the earportz another try. Long story short I use the earportz all the time. Compared to the grey oval silicone tips the earportz open up the sound stage and everything is clearer. Bass is definitely improved. Imaging instrument separation are fantastic.
Also, like Del Griffith, I first bought large and x-large tips since I used the large oval silicone tips but this was a mistake. I now use medium earportz with added spacers for a better and deeper fit.
Also, the sizes listed on the earplugstore website and the size indicated on the actual earportz tips are not the same. Earplugstore has the sizes as XS, S, M, and L but the sizes indicated on the actual tips go from S, M, L, and XL.
I highly recommend the earportz.