If you can put the original springs back on it would be worth another thousand or so...also the exhaust. Older buyers will not look at one thats lowered and with a hot exhausts etc. In Townsville I'd reckon on $7000 if original and $6000 as described. Have to be less in the big smoke. Unfortunately most buyers now don't want petrol eaters which they consider the V8 to be...even the V6 is considered thirsty. As a trade-in they laugh at you. Sad but true.
I actually took out superlows to put in the springs I've got now. I hear you on the petrol thing, especially these days, mind you it don't cost much more to run than the missus' V6 VS. We do similar km's and it costs me maybe $5 more.
I'm in Perth and most seem to go for over $7000, I was hoping for around that.
It would also be nice to sell it within the next 400km - once it hits 200,000km you'll lose some more $$$$.
Have it as clean inside as a whistle, smelling nice, polished so it glistens, Bert Kampfert playing quietly on the CD and parked against a background that compliments the colour of the car. If potential buyers say 'but its got a fuel-burning V8!' just say 'well, its a Calais and they're considered a luxury car with a powerful smooth engine. Economy is secondary if you want the best'....or something like that. Good Luck.