I've also extended the lower edge of the cab with a strip of 40 thou all round which when cobined with extending the depth of the middle windscreen and add height to the communication doors radically changes the proportions of the front end, but in a subtle way.... If 'radical' and 'subtle' can be used to describe the same thing! It look right, well it does to me anyway.
The actual bought in components are small in number - the main items are the Shawplann fan grille and lazerglaze pack and the Brassmaster fuel tanks, forgetting about the running gear for the time being. I scratchbuilt the water tank, not hard as it's just a box, but I mis-read my measurements and made it 2mm too narrow!
So I sliced it in two and added a frame of 2mm strip from Evergreen and stuck it back together! The rest of the underframe is simply plastic and brass strip. 2mm 'H' section from Evergreen makes up the back bone of the chassis frame conversion. I used Jim Smith-Wright's method as a basis but I think I have gone a bit further in terms of the number of seperately components. But he has a large number of items to build for New Street so time does come into it!
The Penbits class 37 bogies seem to place the side frame where they should be - I've narrowed all the bogies of any Bachmann class 37s I've since they first appeared ten or so years ago. It makes a big difference! Though I still maintain the best class 37 I've seen was from a 1983 Railway Modeller which had been rebuilt from the old Triang-Hornby model!