Installer here. Compustar is a great brand. It just makes sense they way they do things. The "extra parts and labor" on your car is going to be a bit more because of 2 different types of systems. If you go with a compustar 6000, 6200, or 6300 brain you'd use 1 BLADE interface module for your Immobilizer bypass, and another interface module (flcan or ads) to do your convenience (locks, factory alarm disarm).
There are both $100 a piece and a shop will most likely charge install on both interfaces (about $30 a piece).
You CAN use a 556U and give up a key but I think using 2 interfaces is a better option.