Just had my shop install a MSD coil, and Delco rapidfire sparkplugs. They orginally installed it with 7mm wires, but told them I had wanted MSD wires. I bought a set of MSD 8.5mm wires and had them install them.

Since they have been installed seems like the car is misfiring a bit when driven a bit agressively. It had never done this before. I also notice sometimes while idling which is normally at around 800 rpm the tach will jump to 1100 rpm for a second then jump back down. I took it back to the shop and they claim due to the new coil, wires, and plugs I need a better ignition module (they said to get Accel) which is causing my problems. Does this sound right? For whatever reason I'm more inclined to think a bad wire since it was working fine with the 7mm in there. Any thoughts? Thank you.