Well with "all things being equal" I guess that also means the drivers would be equal the MKIV would slightly edge out the FD, but not by much at all. Most stats I've read put the FD at around 13.8-14.0 in the 1/4 and the MKIV at around 13.6-13.9 so it's pretty close. Most races I've witnessed in person verify this as well. The difference in feel of the two cars is night and day. The FD feels like you're getting shot out of a slingshot and the MKIV is just kinda numb and washy. After test driving both the FD was the clear choice for me, but thinking back on it the MKIV might have been the better choice due to their reliability and interior room (I'm 6'4"). The auto MKIV is faster because it can build boost off the line by braking and between shifts it doesn't loose boost like a manual tranny car would. Driven properly the manual car is potentially faster, but most people who own MKIV's aren't that good at driving.