This topic has been discussed a lot on other forums. I'll ask you guys about it.

The JB4 is a tune that can add as much as 80 crank hp without any other mods to a 435i (335i also). It's a relatively simple 30 minute installation tapping into the ECU. I'm sold on it. I did a lot of recon trying to find stories involving damaged engines, trannys, etc. associated with using this product. I found none. I need to be super cautious as I will be leasing. Prior to taking the car in for service, the piggy back is removed and any trace of tuning is undetectable as all codes clear. The company does recommend a 500 mile break-in period before installing.

80 hp is a lot more than 34 that the ppk gets you. Granted, the PPK does give you total peace of mind given its warranty coverage. But frankly, until I hear a bad story about the JB4, my mind will be at ease. Does anyone else have input regarding this?

You take a risk when you modify your car with non OEM parts

With that in mind. There are lots of BMW owners with aftermarket parts that are doing just fine. Does that mean this JB4 tune is as safe as the PPK? Well probably not. More power = more stress.

But in terms of value... The JB4 wins.

Do your research and if you feel good about it. Go for it. 80hp is alot of power.

Agree 100% with your points. Wish me luck!