Wow, where to go here....
Let's start off with....
I have done A LOT of Keisler installs. I have even fixed a few that others had "professionally" done. For the most part, the (what did you call it T? Oh yeah, package), fit exceptionally well. They are a well thought out conversion, and that is the key word. Conversion. This is not a transmission that was built originally with your old iron in mind. You will find that the cars they were made for were also made to accomodate that transmission. Mother Mopar built her cars to accomodate the trannys she was using at the time. Seriously, Mopars have some of the biggest fricken shifter humps I have ever seen. How much "Hacking" do you have to do when you convert a Mopar to a 4 speed? If you want to "modify" your car with the intention of "putting it back to stock" so you can sell it for Barrett money, I suggest you stick to valve covers and a shiney air cleaner. If you want to do a conversion that will make your car way more enjoyable to drive, consider giving Keisler a call.
Any conversion has the potential for problems, whether it is installation, parts OR the technician. It's part of the hobby, it happens. Nobody is perfect. (Hey T, how many wives do you have?) I have had bad customer service, and I am sure that I have given bad customer service. We're human, we all have our days. I will say that I have dealt with Keisler for years and have never had a problem with them in relation to customer service. I have spent a considerable amount of time with Shafi Keisler and can tell you that he takes all of this very seriously. This guy is not only building stuff for your car, he is EXCITED about it and your cars. If you have had a bad experience with them, I don't know what to tell you. Could be you caught the rep on a bad day, could be you were having a bad day. I am just putting it out there.
That being said,
I've done both the 5spd and the 6spd conversions. Both are killer sticks. The 6spd will take a lot more work because it is a physically bigger trans. You just have to asses your needs in a transmission and your ability to do the required work.