The key is in the responses in posts 2 & 3 above...
The tax bands for cars first registered before & after some date around March 2006 changed. Top tax band cars registered before that specific date are cheaper (by a long way) than the same car first registered after that date.
For an exact answer by specific car, use the links that intothevoid provided in post 3.
I was lucky enough to find a 350 registered in early March 2006 so £280 road tax. Just a few weeks earlier I nearly did a deal on an 07 280 until I found out it was £470 road tax.
If you are looking for one be aware of the well documented balancer shaft problems.
My SLK350 is registered "25/4/06" so I get clobbered for 485.00, but I just pay monthly for a small fee. Before I used to pay it in one lump, but now it's just 44 quid and a few pence per month, so I find that doable...:smile: