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I'm of the opinion that an XML sitemap is unnecessary, IF your site navigation is in order. That said, though, we all know how easy it is for a five or ten thousand page ecommerce site's navigation to get out of whack.

The bottom line, I think, is that it costs nothing but a few minutes to build and submit, and it can't do you any harm. Cheap insurance, no?

I agree that having a video sitemap is a good idea. I'd also recommend that you take the opportunity now (when just implementing videos, which you'll presumably continue) to implement some HTML5 markup on those videos. Let the search engines know who and what the videos are about, and maximize your benefits.

I guess I'm not quite as polite as the rest of these folks. As far as I'm concerned, article spinning, at its best, is spammy and does the client an injustice. At it's worst, it's theft, as many spinners start with someone else's work as a base.

Neither definition fits what I think my clients deserve.

I definitely don't agree that article writing is a thing of the past. What I think IS a thing of the past (at least, I HOPE so) is low quality articles, spun articles, and the thin content that so many directories have accepted, pre-Panda.

In fact, my business has exploded since Panda was released, as people scurry to acquire quality articles to replace the watered-down garbage they were previously buying for .01-.02 per word.

So I'd say no, it's not a dead practice, but going forward, it's going to take higher quality to be effective.

As Loudogg says, with a 301 redirect you'll be fine, although you will experience a slight loss of link juice through the 301. Further losses can be avoided by ensuring (as much as is possible) that links are directed to your destination page, so they don't go through the redirect.

I'd definitely make sure to implement a rel="canonical" directive, and focus on being consistent.

I agree that there's no longer any difference to the crawlers. However, one other thing worthy of consideration is the possibility of moving the site to a new URL. With relative URLs, you may be saved a lot of painstaking work, whereas with absolutes, every single page will have to be rewritten. There are tools to assist in the task, but it's still a lousy job to undertake.

I would seriously consider the possibility of making only as much of your site https as is really necessary.

That said, the portion of your link juice being lost due to the redirects is probably relatively insignificant. But if you could keep half the site as http, that would cut your leakage in half.

I agree with Oznappies' recommendation... tell them "this vehicle has been sold, but we have other similar models". Personally, I would offer them a link to similar models and a Back link, as some people will take exception to being led to a different car than the one they wanted to see. I would definitely not get rid of the old content, however. I would simply do a noindex follow.