I'm not sure how those others sound, but I went with Infinity Kappa based off of various reviews and price. I have little basis for comparison as I can only really comment against the stock speakers. The Kappas are stronger than my ears can take. The tweeter is broad in regards to the range of notes it delivers, and seems to have an 'in your face' presence...very strong as if it thinks it's a 4in speaker. I use a 10in sub and no rear speakers. I also use a 4 channel Alpine amp for the Kappas. The crossover modules fit inside the front kick panels.
I did not need to use spacers for the install, but I had to rig up the mounts a little...all included. Amazon is your friend.
This is a subjective thread, so just offering you this option.
Infinity 609CS 270W (Peak) 6-1/2 x 6-3/4 Two-Way Component System Speakers (Pair):Amazon:Car Electronics