Originally Posted by MJ777LR
After doing a lot of thinking, I'm actually leaning towards the Jehnert Flatlines and the XD600/6. What I like about the Jehnerts is that the entire set is tuned to work together. As much as I'd like to add an MS-8 and do my own tuning and adjustments, I'd also like to keep the setup simple. This seems to fit the bill. And, the spacers and adapters come with the set as well, eliminating a lot of time and effort which would otherwise be spent fabricating your own rings and such.
Nothing is "tuned", you still have to use the crossover on the JL amp to make the two sets work together. And then you are still stuck with an un-tuned system. Just because the HiFi signal is flat, does not mean that the frequency response in your car will be flat. You will end up with plenty of peaks and valleys, no matter which speakers you choose. The Jehnerts don't sound better than their competitors just because they were engineered for German cars. Also, don't think that because it is the same line, that the speakers are perfect for each other. This goes for other brands as well. If you know the type of sound you like, and you could do A/B testing before you buy, you'd probably end up with components from brand A, woofers from brand B, and perhaps even a sub from brand C.
Not trying to discourage you from your decision, just pointing out that "mix-n-matching" works quite well in the audio world, and that no matter which speakers you choose, you would still need a processor to get everything "tuned to work together".