How many responses do you want? Tires and oils will produce dozens of different answers. For tires, Milage, grip, is an inverse relationship. As one goes up, the other goes down and vice versa. And then you have cost to consider.
Corsa's are good tires, grippy, but will provide lower milage results.
Dunlop D208's, people swear by them. Metzler M-1 Sportec, are also great. A bit long in the tooth in terms of new tire on the market, but hey, the new BMW is shod with them.
Ok, so here is my opinion:
I have 25K on my 02 SE, I have had the BT56, D208's and M-1's. All had thier good points. For now my taste is on the M-1's. They have a bit more feel for me than the D208's and BT56. The M-1's return less milage than the D208 an BT56.
Avon, Dunlap, Pirelli, Metzler, Bridgstone, all will work. It's just what you want.
Stealth