You mentioned that the suspension was stiff, does it feel like it jerks a lot? Cause I just started learning stick so I could possibly get this car (got a 2011 Fiesta right now) I've been driving my friends Jetta, which is very smooth. I drove my friends Honda S2K (a performance car obviously) over the weekend and it was extremely stiff and jerky. Is this what the ST is like?
It is really hard to answer questions concerning what is stiff or not. I find the spring rates and dampers to be perfectly matched, meaning there isn't any harshness over bumps. Typically from what I have found, a harsh ride comes from having a high spring rates without a matched set of shocks/struts. The spring compression isn't dampened properly, so the ride feels harsh. Having too high dampening makes for an uncomfortable ride. I once left my Koni's set to full stiff for the drive back from an autocross and the ride sucked. The spring rates on my Mustang are roughly 4 times that of stock, but with good dampers, the ride is actually pretty good. This is with either urethane, steel, or aluminum bushings and a Kevlar seat. You feel everything on the road with that setup.
There are a lot of factors that go into ride quality and ride perception. Low profile performance tires with high pressures will increase transmission of bumps into the chassis. A stiff chassis will also transmit more feeling to the driver since less forces are being used to twist or flex the chassis. The durometer of the seat foam changes how you feel the bumps. The level of insulation can change your perception of ride quality. Then you get into bushing durometers, unsprung weight, spring rates, and shock valving.
Personally, I find the ride quality to be fantastic. Stiff, controlled, provides great feedback, and produces terrific amounts of lateral, acceleration, and braking traction. Of all the cars I have owned, the SVT Focus and the Fiesta ST are probably the only 2 that would not need a complete new suspension. Both also are the only cars that I have owned (or will own) that don't need performance tires. It is great that the factory produces cars that don't need a list of modifications to make them perform.