[TYPO3-english] Where to put setup and constant definitions?

[Benoit Montereau]

In the introduction package for Typo3 4.7 the definitions (constants ans
TS) are mainly done/included in sysfolder (that means in the database) and
in the same package for Typo3 6.0, all the definition are done in external
.ts files.

Does exist a better method? Is the new one better regarding performance?

By the way, could someone let me know if all the extensions compatible with
4.7 should be rewrote for 6.0?

Thank you in advance for your help.
Regards,
BM