Yeah on the page for the head unit on the right there is a icon saying message seller. I've just messaged him saying I'm ready to buy :slayer: but he's offline so don't expect a reply until the morning.
On negotiation I wouldn't expect to get a better price than whats already been said. The seller has told me that he makes very little profit on this at that price :bang:. Which makes sense he is the cheapest seller on there by a country mile.
That's very true, many other sellers on there are selling there's for $425 whilst he's selling for $340 delivered so he must be tight on profits