Lotus founder Colin Chapman said:
"To make it go faster - you will have to add lightness"
Unfortunately he is also quoted for saying:
"You won't catch me driving a race car that I have built"
(This last remark was obviously tongue-in-cheek, as numerous photos exist of Chapman driving racing cars he built.)
Following the first sentence the "dogme" for modifying or rebuilding a Seven must be:
"keep it light, strong and simple"
I must admit I am not a purist. I have not brought a Seven for keeping it completely original. Sevens has always been modified and tweeked by the owners, and I like the way the car can be upgraded and personalized.