I'd agree with you Jon, state of tune matters, perhaps second only to weight of right foot... Lorin, if you're willing to take the comparison Ian came up with between his manual 24v and my auto 12v on a heavily laden & relatively high speed trip as any sort of real-world guide, then don't spend a fortune on a conversion: If your planned trips add up to 13500 miles and you use the car a bit more anyway in the next few years you might clock up, for the sake of argument, 20,000 miles before you need a minibus for all the children ;-) 20000 miles at 20 mpg is 1000 gallons or 4546 litres at say £1.45 per litre gives a fuel cost of £6591.70. Improving this by 10% will save you around £660 which probably won't go that far towards a 24v conversion?
All the best,
Toby
1994 HDJ80
1990 HDJ80 (sold)