[swordtart]

If memory serves the deluxe edition contains only straights and curves (with debris versions of both).

Curves contains tight curves (which may well be useful if you are trying to create hairpin bends).

Intersections contains all new road sections, cross roads (which might be useful for figure of 8 circuits) and turn-outs (which would be useful for pit lanes and those tracks that have alternate routes).

Straights are probably least useful as there is nothing in it that you couldn't photoshop from your delux versions.

All include some extra counters for different coloured paint and other dropped counters, but again nothing critical.

Boardgamegeek may have some low res scans so you use to assess the value to you.

Dueltrack contains all these, plus some others (short junctions),plus examples of how they can be combined to create some real world race tracks (and some fictional ones). It also has some new racing car counters and pits etc.

The gas engine rules have been largely superceded, but the chassis and crossbow rules are quite good fun (and you can hand wave away the different gas engine stats as an artefact of this iteration being set at the height of the troubles)

I would strongly recommend Duel Track for the road sections alone, but the focus on racing may give you bonus material to use as well.
EDIT.

A word of warning however, Dueltrack road sections need some "stitching" together as the PDF pages are not apparently compatible with the card road sections. For some reason they are printed on two pages. If you are even slightly competent with paint you can cut and paste them back together without too much trouble (though arguably if they had been scanned right in the first place there would be no trouble at all).