Buying A4 B5 or B7 1.8T for tuning (K04)
 

Hello, I have Audi A4 1.8T Quattro 1995 (first one ever made :)). I have it for the past 15 years and it is time to change it. I only have chip, 710n, lowered coils, LPG system. It has over 200K miles, but still good.

Anyways, I will buy new car and tune it - I want to go K04-064, or at least Hybrid K04, aiming close to 300HP (crank), so 240WHP possibly. I cannot decide between:
- 2000 A4 1.8T quattro manual, with low miles (below 100K)
- 2006/2007 A4 B7 1.8T quattro manual S-line (USP)

Few questions:
1. B5 is about 200lb lighter, how much of difference does that make, that is my main concern?
2. Are both 1.8T engines internals safe with that power (lets say K04-064 moderate boost)?
3. Reliability of both cars, since I plan to find low milage one and have it for at least 5-6 years.
4. Other thought which one to get b5 or b7?

I did not consider 2.0TFSI, since I am afraid of oil issues and reliability, 1.8T should be safer and simpler, and with K04 still will make similar power.

Thanks