jtbo the only mods i plan for the rear section of the car is to continue the belly pan all the way to the back. I have already taped off some gaps but i dont want to put a boat tail on the car because it already gets plenty of attention and i dont think i need any more. I may however install airflow trip features which might do something and wont look very strange.
Also you are correct the 626 hatchback has a good angle (could be better but still good) unfortunately i have the sedan so there is a fairly abrupt angle between the top of the cabin and the rear window. This is where i may place the airflow trip feature
Dennty good ideas, Block heater i do not have to worry about as i have lowered my idle at cold start up. using a self made electronic control system for the idle control valve and i have blocked off the mechanical air bypass which activates at cold start. This means i get very low fuel usage at startup. A block heater would provide a little advantage however i think with my car in its current state it would cost more in electricity than the petrol savings. If i was in a cold climate then this would be different. (it only very occasionally goes below 0 here in melbourne australia)
The manual transmission is a dream of mine and i will definitely be buying a manual car for my next car however to change out the transmission it is such a large job that it would work out better to just buy a new car and trade this one. In hindsight maybe i should have done that at the start of all of these mods
Regarding LRR tires as mentioned in the initial post it will work out cheaper for me to stay with normal tires. I am actually in the process of getting some tires so i have only just recently done the sums. If i had a new car i would definitely get LRR tires but i dont expect to have the current car i have in 4 yrs which is when the payback time is.