I would say the F1's cornering speeds are way higher.
IIC an huge problem of these Group C cars was balance, the front was always lacking downforce. Then the teams started thinking about front diffusers and wings, this reduced the problem, mostly the front diffuser on the Eagle Mk. III was pretty succesful. the wing was an more sensitive an less efficient solution. The 'Wing' was imo more driven around the idea to allow to set the car up better and ultimate downforce, overall it is an less efficient solution.
For example the XJR-14 had this front wing, but with the Bi-plane wing the problem the front wing reduced was back again really quickly. The XJR-14 still had an huge understeer problem. Lter solutions of the wing had not, but were incredibly draggy, for example the 905 Evo2 and Allaard J2X-c. The latter even had the problem of when the lower tier of the rear wing its angle was increased the front downforce increased too, on paper this sounds good, on track it is not as it makes setting the car up more difficult.
To come back on the mix of an F1 car and Group C car, the Peugeot 905 Evo2 and allard J2X-c were an real mix of F1 and Group C, with the front wing ad raised nose. The wheelcovers where only there as required by regulations(although they are useful)