I can only point you towards this post, which I posted after mine was done. I am still very pleased and would say that both companies will give you a good service. A few quote bhp her or there is neither here no there as it is all good.
Posted - 18 Mar 2003 : 21:33:39
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1.4Tdi,, got mine chipped today by Impossible Performance in Kent..
www.impossible-performance.cwc.net
I decided to have my car tested on a rolling road first and afterwards and not by the chipping company,, this allowed me a degree of honesty in the results.
Before chipping: 81BHP and 198Nm. With cruise control set to 2750rpm in 5th gear on the motorway on a level stretch of the motorway, DIS reads 46.7mpg.
After chipping, same technician, same rolling road: 112BHP and 258Nm. With cruise control set to 2750rpm in 5th gear on the motorway on a level stretch of the motorway, DIS reads 48.9mpg.
So how does it look,, well first off the chip is in one of the many compartments hidden under the passenger front seat.. The chip itself is no different than the one that comes out,, which you are allowed to keep. It would take a very sharp and extremely keen eyed Audi Technician to notice the difference visually,, and there is no reason for him to be looking there in the first place..
Previously my new Tdi would prefer to be in the 2000rpm – 4000rpm range for any action to take place. In slow moving traffic it preferred not to be left in 5th gear at revs below 2000rpm and if you did it was not comfortable. This meant for many gear changes which for a guy who has just come from an automatic V6, is a pain.
When it comes to action the standard Tdi comes alive at about 2500rpm and is not happy above 4000rpm.
WELL NOW,, things are different, very different. The car pulls from 1500rpm in any gear and it pulls strong from 2000rpm and by time you get to 2500rpm,, watch out this baby is coming through like a train about to discover sex for the first time.
There are no flat spots in the rev range and you have to watch how you pull off in 1st and 2nd gear as the sheer quantity of torque will have the steering wheel fighting in your hands.