Grant,
To much bolster? OMG! Check out the second pic on post 84. I removed almost all of the stock bolsters. The little bit I added back I flared out, providing much more room. I'm 5'10" with a small frame and felt like I was in a NASCAR style seat. I added the hump between the legs to help keep me in the seat (it looks really good too). Having a bad back, I was unable to get out of seat then exit the car. Now I can swivel my legs out easily and my right tricep doesn't hit the shoulder bolster when shifting. I am very pleased with the outcome of the plug.
I planned on the tillet B5's, but my seat is very close in measurements for a fraction of the price. If we are successful with cf, any slight difference will be hardly noticeable.