almost all head units are "xxx" ready. if they have it built in, then they lack some other features or a lower end sound processor/ internal crossovers or stuff like that
After reading this entertaining thread, I would suggest you just buy and OEM replacement speaker if your not willing to shell out the money to do it right.
jensen is not bad right, my GF give that that for christmas, just have to make sure that it can work with the universal TV tuner. i hope it does, cause i like to watch tv in the moring for news and stuff while driving to work.