Adding a tight fitting stock, such as Choate or Butler Creek folders, or the Choate E2 Pistol Grip stock will cut your group size. My two Mini's, with scopes and Choate stocks shoot 1.5" groups.
I have a Tasco 4x40 on one, and a Simmons 3-9x40 on the other. These are not great scopes, but the addition of a scope (these two are Ranch Rifles) are a great improvement over the irons of the regular Minis (I traded these off for the Ranch Rifles I have now).
If you want to expect any scope life at all, use an aftermarket buffer, such as the Buffer Technologies buffer.
Breakfree CLP is what I use, too.
My Minis like all the various 55 gr FMJ stuff, UMC/Remington, Federal American Eagle, Winchester Q3131A, Black Hills, Lake City, South African "battle pack", plus M855 from IMI and others.
You can get PMI mags from
www.deltaforce.com PMI mags run with 100% reliability in my Mini. Most of mine are 30's, but I have one PMI 40, and it runs as well as the 30's.