what might be a realistic zero to 60 guesstimate

[Excaliber]

Run the numbers:

T5 and 3.46 rear gear come out to around 11.6 final drive ratio. A typical Cobra run's about a 9 final drive ratio. A lot, if not MOST Cobra owners and other folks running a T5 complain that 1st gear is basically "useless" because it's SO low!!! It's SO low, in fact, that some folks move up to a TKO JUST to address the ultra low 1st gear ratio of the T5!

My personal opinion is on an 11 or higher final drive ratio is it's a joke! It's cheap (as in expensive) as parts are readily available. It gives the impression of performance because it's very easy to spin the tires. Accelleration is brisk with this low ratio. Shelby did the same thing when there were complaints about the early 260-289 original Cobra's, he simply went to a lower rear gear ratio instead of raising the engine power. This improved the "responsiveness" of the car and satisfied the 0-60 mph crowd. It's a cheap way to gain the feeling of "performance", without actually doing anything to the motor.

...not saying that's what BDR is doing, just sayin', thats one approach to increase performance inexpensively. But at the risk of component failure depending on other options. Like slicks, increased torque/horse power, etc.