Don't bank on diesel dropping this year. I like to think I have a pretty good handle on oil macroeconomics, and trust me when I tell you that the current market has NOTHING to do with the fundamentals; right now we're dealing with an emotion-driven speculative market: oil and its derivatives are high because they're high, not because of product supply and demand.
Diesel is as high as $3.999 and as low as $3.699 in central CT. I watch daily for it to tick over $4.009, at which point the visual/psychological barrier has been breeched and it'll keep going (just like crude/bbl). You should plan your racing year expecting $4/gal diesel, and probably even $4/gal gasoline.
I just hope we get some relief within the new few months, otherwise I expect my home oil heating bill to rise a minimum of 50%. These energy costs have a very real probability of affecting my race schedule, in that I am giving serous thought to skipping the farther-away events such as Mid-Ohio and Road Atlanta this year (especially given I don't have a fully-prepped car; it's a bit expensive to do development/testing 1000 miles away from home...)
This is going to be a turbulent year in the petroleum market, and it's gonna take some serious changes in our economy (good or bad) along with significant changes in demand (i.e., stop using it) in order to bitch-slap the market to recognize the bubble and pop it. But, other than some peripheral indications of a flattening of demand, it's not there yet, not even close.
Your mileage may not vary, but the costs per mile certainly will. Hang on, kids, it'll be a rough ride in '08.
Tom, the V-dubs of that era are bulletproof cars. Get one that's been maintained well and you won't have any problems. - GA