I prefer a DOT approved windshield unless you are going all out with a serious drag only car (8z and below).
They do help with structure as stated but if you are in the lexan/poly window zone chances are you have a rollbar or cage so that is not as much of an issue.
Check my spreadsheet for some ideas. I have managed to get 800# out of my piggy GP.
The first couple hundred #s come out easy,after that start looking for ozs.
Spread sheet has been updated, click on "sheet1"
http://spreadsheets.google.com/pub?key= ... yTNdsrrgMg
They do help with structure as stated but if you are in the lexan/poly window zone chances are you have a rollbar or cage so that is not as much of an issue.
Check my spreadsheet for some ideas. I have managed to get 800# out of my piggy GP.
The first couple hundred #s come out easy,after that start looking for ozs.
Spread sheet has been updated, click on "sheet1"
http://spreadsheets.google.com/pub?key= ... yTNdsrrgMg