Not at all. The car and boat reference is just the extra cleaning heads you get, so this is better than the normal V6 standard Dyson.
I agree. Dyson refurb store on ebay is the way to go, if you can wait. I picked up this exact car and boat V6 for £115 six months ago.
Perhaps the V8? I've heard of poor performance on the V6 here but not the V8. IIRC I looked at both V6 and V8 in Currys and they are very very similar in form. The V10 is lots bigger, probably too big for small space work without a hose.
Referbs with the motorhead attachment frequently appear in Dyson's eBay store for less than this. They come like new with a years warranty. I paid £110 for a v6 three weeks ago. https://www.ebay.co.uk/sch/dyson_outlet/m.html?_nkw=&_armrs=1&_ipg=&_from=
Best to wait for their bigger sales