The exhaust heat will come on almost immediately (only as long as it takes to heat soak the aluminum spacer), which will allow a faster warm-up schedule. You can turn the choke spring back (less tension). I did an experiment with my '95 Jeep GC. It was about 32 degrees out (0 C). I fired the engine, and the injector pulse-width (IPW) went to around 30 milliseconds. After about 10 minutes it was down around 8 ms. Fully warmed up it's a tick over 2 milliseconds.
With the factory ECM control, the engine consumed almost 15X more fuel cold than warmed up! Fuel delivery is increased to compensate for a cold engine that cannot vaporize much fuel -- by a multiplication factor. This means climbing out our hole (steep driveway) with a cold engine chugs fuel. The faster you can turn the choke off, the better short-trip fuel economy will be.
