We've updated the our reliability stats for the B6 A4 and S4 (on our redesigned site) to include owner experiences through December 31, 2011.

Repair frequencies, in terms of repair trips per 100 cars per year:

2005 A4: 111, about average

2005 S4: 125, worse than average

2004 A4: 98, about average

2004 S4: 113, about average

2003 A4: 112, about average

2002 A4: 143, about average

We have two additional statistics, "Nada-odds" and "Lemon-odds," to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop.

These statistics:

2002 A4: 12, 15

We'll have further updates in May and August. The more owners participate, the better the information we can provide to everyone.

To see how competitors compare, and to sign up to help improve this information:

Audi A4 reliability ratings and comparisons

Audi A4 Lemon-odds and Nada-odds

 

We've updated the our reliability stats for the B6 A4 and S4 to include owner experiences through June 30, 2012.

Repair frequencies, in terms of repair trips per 100 cars per year:


2005 A4: 70, about average

2005 S4: 71, about average

2004 A4: 87, about average

2004 S4: 105, worse than average

2003 A4: 62, about average

2002 A4: 106, worse than average

We have two additional statistics, "Nada-odds" and "Lemon-odds," to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop.

These statistics:

2002 A4: 34, 4

We'll have further updates in November and February. The more owners participate, the better the information we can provide to everyone.

To see how competitors compare, and to sign up to help improve this information:

Audi A4 reliability ratings and comparisons

 

We've updated our reliability stats for the A4 and S4 to include owner experiences through September 30, 2012.

Repair frequencies, in terms of repair trips per 100 cars per year:

2005 A4: 48, better than average, small sample size

2005 S4: 64, about average, small sample size

2004 A4: 95, worse than average

2004 S4: 100, worse than average

2003 A4: 45, better than average, results for other model years suggest that this one might not be accurate

2002 A4: 128, worse than average

We have two additional statistics, "Nada-odds" and "Lemon-odds," to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop.

These statistics:

2002 A4: 30, 11

We'll have further updates in February and May. The more owners participate, the more precise these will be.

To see how competitors compare, and to sign up to help:

Audi A4 reliability ratings and comparisons

 

We've updated our reliability stats for the A4 / S4 to include owner experiences through March 31, 2013.

Repair frequencies, in terms of repair trips per 100 cars per year:

2005 A4: 57, moderate, small sample size
2005 S4: 56, moderate, small sample size
2004 A4: 99, high
2004 S4: 97, high
2003 A4: 39, low, small sample size
2002 A4: 112, high
2002 S4: 55, low, very small sample size

We'll have further updates in August and in November. To see how competitors compare, and to sign up to help improve this information:

Audi A4 / S4 reliability ratings and comparisons

 

We've updated our reliability stats for the B6 A4 / S4 to include owner experiences through June 30, 2013. (Another source is about 14 months behind.)

Repair frequencies, in terms of repair trips per 100 cars per year:

2005 A4: 80, moderate, small sample size
2005 S4: 65, moderate, small sample size
2004 A4: 96, high
2004 S4: 117, high
2003 A4: 75, moderate, small sample size
2002 A4: 107, moderate
2002 S4: 53, low, very small sample size

We'll have further updates in November and February.

To view competitors' scores and descriptions of reported repairs, and to sign up to help:

Audi A4 / S4 reliability ratings and comparisons

 

We've updated our reliability stats for the A4 / S4 to include owner experiences through September 30, 2013.

Repair frequencies, in terms of repair trips per 100 cars per year:

2005 A4: 98, high, small sample size
2005 S4: 67, moderate, small sample size
2004 A4: 72, moderate
2004 S4: 122, high
2003 A4: 74, low, small sample size
2002 A4: 98, moderate
2002 S4: 84, low, very small sample size

We'll have further updates in February and in May. The more owners participate, the more comprehensive and precise these will be.

To see how competitors compare, and to sign up to help improve this information:

Audi A4 / S4 reliability ratings and comparisons

 

We've updated our reliability stats for the A4 / S4 to include owner experiences through December 31, 2013.

Repair frequencies, in terms of repair trips per 100 cars per year:

2005 A4: 99, high, small sample size
2005 S4: 59, moderate, small sample size
2004 A4: 63, moderate
2004 S4: 122, high
2003 A4: 73, moderate
2002 A4: 129, high
2002 S4: 101, moderate, very small sample size

We have two additional statistics, "Nada-odds" and "Lemon-odds", to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop:

2002 A4: 25, 12

We'll have further updates in May and in August. The more owners participate, the more comprehensive and precise these will be.

To see the repairs behind these stats, and to sign up to help improve this information:

Audi A4 / S4 reliability ratings and comparisons

 

Our reliability stats for the A4 / S4 now include owner experiences through March 31, 2014, making them nearly a year ahead of other sources.

Repair frequencies, in terms of repair trips per 100 cars per year:

2005 A4: 103, high, small sample size
2005 S4: 44, low, small sample size
2004 A4: 78,2005.5- moderate
2004 S4: 119, high, small sample size
2003 A4: 64, low
2002 A4: 147, high
2002 S4: 135, high, very small sample size

Thank you, once again, everyone who has been helping. Next update in August.

For a deeper dive, including the stats for other cars and repair descriptions, and to sign up to help improve this information:

Audi A4 / S4 reliability ratings and comparisons

 

I've got some questions bout my A4 2.0L, I want some more power without upgrading to a Turbo. I've spent so far on Branches, Wildcat freeflow and BMC induction kit. I despratly need more but don't want to brake my own wallet of making her too heavy on fuel consumption.

 

This thread focuses on reliability stats. You'll probably get more of a response if you ask for engine mod suggestions elsewhere.