Welcome to Ecomodder Charlo49! I'm siding with cowmeat here. If you look over the website, you will find that all 5 of the mods you listed will be in a place called the Unicorn Corral 99% of the time. There has not been any A-B-A testing done to confirm their advertised gains, so they are considered baloney until proved otherwise.
I would start with the 2 links below. These are the mods that actually work, and most of them are free or easy on the wallet
FWIW, I have increased my fuel economy 35% with utilizing only some of the mods!
65+ Vehicle modifications for better fuel economy - EcoModder.com
100+ Hypermiling / ecodriving tips & tactics for better mpg - EcoModder.com
I would start with these 3:
-Adjust the nut (you!) behind the wheel
-ScanGauge, UltraGauge, Torque, etc.
-Coasting to stoplights and stop signs
