only my persoanl view, but std Corsa's are probably the worst tyres i've had - the grip and feel was useless (on a 998). Damn back wheel used to frequently 'step out' .
I've got 207RR's on now- much grippier and better feel and last fairly well.
Also lets the bike turn-in better, and still only £140 a pair (if you shop around).
On my race bike, i run Pirelli Supercorsas (same tyre as Rennsports) - fantastic grip once up to temperature, but don't last long!.