Welcome to Gadgetman Land, Clinton!
First, I want to remind you to make a post on the Welcome Mat. That way, everyone else who has will be notified of your finding the family and can welcome you properly. Just tell us some of your history and why you came here and what you hope to accomplish.
I am so very pleased at how excited you are! That's the way I was when the first vehicle I did went from about 225/tank to over 660. Yee-HAH!
The residual smell will fade to a greater or lesser degree over a short period. What's happening is the residue that's built up in the exhaust system is being washed out by the extra steam created by the improved combustion, washing it into the cat. That's why it's less intense, and smells different.
On your Grand Caravan, you should see somewhere in the 60-100% range of an increase, and the same with your 98 Ford. Both are ideal candidates for The Groove. Of course, Snake Oil is recommended for all vehicles, as it tightens the engines up while friction-proofing the parts. It will also substantially reduce the blow-by gases even more than The Groove, and will reduce it even more.
One client reported 25-40 PSI increase in the compression on all cylinders.
Not too shabby,. if I do say so myself!
You are going to LOVE living in Gadgetman Land!
Welcome home.