Having had 4 DC2's, 3 DC5's, currently an EK9 & ATR, i'll comment.
Stock - There all very sorted cars, to be honest theres nothing in it handling and grip wise, its all pretty much the same. The difference is the torque, gearing, and more so the sensation of it all, i.e the DC5 stock is boaring and not as involving to drive as the DC2. Lap times, you would see very little difference from a DC2 and DC5, with the EK9 only a tad behind.
I find the EK9 to be the more involving drive and better handing car out of the box. The DC5 has all the grip it needs, and is easy to drive, with alot less lift off than the others. The DC2 if find has bit more front traction/grip available than the EK9, but the rear is alot more float, in high speed bends you really notice it. The EK9 is a like, but just has a more controllable tail, the snap i find is alot less.
If your a driver who wants to feel everything the cars doing and be more involved then the DC2 & EK9 are the ones to have, if your not such a great driver and what grip, a stable back end, and want to go fast, then DC5 is the one.