Price is a function of speed and patience.
If you look around, you can do a T5 upgrade for under $600 easily. I got my first T5 for $250 rebuilt and shipped.
I'd save a few hundred on the ignition and just do a DS2. Dollar for dollar, there are better ways to squeeze out HP at first then the ignition. Once you are at the top end, next year get the DUI.
Using some of my old numbers:
1) DS2 - $150
2) T5 upgrade - $600
3) 8" rear end with 3.55 gears: $300
4) Headers -$400
5) New Cam -$250
6) V-8 5 Lug front end - $200
Save the rest until next year, or at most put a 1-2V adaptor on there. If you look around, you can get an Offenhauser 3-1V adaptor and carbs for the last $600 and combined with the above will give you some fun times and enough work to keep you busy for awhile. If you take your time you can get really good prices (I scored my v-8 front end and rear end for $125 total, including all the steering, spindles, etc.).
If you want bolt on power quickly, a CI or Oze 250 head and intake and the DS2 ignition. Both relatively quick and easy to do. However I think both will kill your 3 speed and rear end fairly quickly. I know once I put my Oz 250 head on my rear end chewed itself up in 3 months due to my spirited driving caused by the new found power.
I am however a proponent of safety items first when you plan to build for speed. At a minimum. dual Res master cylinder.