Depends how you define "quicker"?
It's got a lot of torque and reasonable power, but there's a lot lost through the drivetrain and it's a big heavy car, so don't expect too much and stick to your strengths*: big open roads, gently sweeping high-speed corners, etc. I'd expand on
@Rhyso 's comment "choose your victims wisely".... I'd say "choose your victims carefully!"....
What are you after for comparison?
Total bhp?
BHP/ton?
0-62mph?
Mid range acceleration? (e.g. 50-90mph)
Top speed?
Around a track?
The BiTDI's main strength is within-gear acceleration and then also after that, there's the quattro drivetrain, but it shares that with any other Audi A4 upwards...
As
@Roadrunner146 mentioned: The most immediate competitor would be a tweaked/remapped A6 TFSI (3.0 supercharged)... it's got levels of torque comparable to regular single turbo 3.0TDI , but N/A level of throttle response and pulls to ~7000rpm, so you're looking at ~400-450whp with a pulley change (£500) + remap (£300-£500)... plus it is lighter than a BiTDI, so even a mildly fettled one like mine would be a fair bit quicker: despite less torque, I've got ~100whp more already... and in a lighter car... 0-62's usually around the mid-4's with a just the remap and at least the low 4's with a pulley+remap. Best I've heard of was a pulley, exhaust and extensive custom remap getting a dyno-confirmed 490whp, which I believe equated to a 0-62mph in ~3.7sec, although I don't know if that was ever tested with timing gear, but that sounds easily viable given that it's sitting between a S6 and RS6 in terms of power (420PS / 560PS, so probably 350whp / 450whp ballpark?)
In terms of top-speed - you'd need to stick mostly to remapped and de-restricted cars: an A6 TFSI will get ~175mph-190mph with most pulley + remap setups... probably more for my friend's one with the custom remap.
*All that said, the other cars I tinker with are WAY fast than any A6 (or RS6!) around a tight track: something like a turbo-charged MR2 Spyder is 210-240whp and weighs <900kg wet (in track spec) and it leaves people gob-smacked when feel them go around corners... once you put decent tyres and suspension on them, you need specialised baffled oil sumps otherwise the lateral G's mean the oil can't get to the bottom of the sump to be drained... but I wouldn't want to drive one at a high-end A6 cruising speed! Like I said - let each car stick to their strengths