Hi, I have been browsing this forum on and off for the last 2 years but only signed up today. I'd like to say hi and some history of me and aircoleld VW's before I punt my question/s

For those that are not interested in intro's feel free to skip to the bottom of the post for my questions.
I'm turning 42 this year

and have owned VW's since when I was 18. My ownership of VW's goes back to 1953 Type 1 to 1980 Type 2. I believe at last count this may be around 30 aircooled. At present I own a 1965 Type 2 and a 1964 Type 1. I started buying VW magazines and modding my VW's since 1988. I owned a Squareback in 1988 with an 1835, wild cam and a 1953 Beetle, stock. You get the idea.
ok, my love affair with the Cal look started with the Custom Beetle book. Great cars from G BERG and the other historic names. forever got my attention. My VW mods never went too far. Some BRMs here, a nose down job there were as far as I got. My splitty is lowered with a 1915cc.
The goal: Going forward I want to restore and build a VW beetle, to Cal Look specification. Real old school. I this to be a car I cherish and be part of the family. I am selling the bus soon so this should net me AUD $40,000. The balance I have remain after the Cal Look build will go towards a new kitchen
The basics are there for me.
1. Nose down
2. Nerf bars
3. Recapped slicks with threads
4. 2.0L plus engine
5. One piece windows
6. No side trim
7. Cal Look window rubber
8. Single factory colour paintjob
9. Hillborne mechanical injection
10. and so on
Questions:
1. I like the early pre 67 shape but am also thinking balljoints and IRS. Should I look at installing a post 67 balljoint pan and IRS it ?
2. How are launches from the start line affected with the use of IRS as opposed to swingaxle?
3. Should I go 4spd or 5spd? How does this affect straight line performance?
Thanks for having a look. I would really appreiate some feedback. As time goes on, I will start my project and will definately have more questions.