How much power do engine mods yield?

My apologies... I try not to be a "fanboy" by backing my contentions up with various and sundry "facts and figures," such as the Wallace website computations and the videos that show the cars I champion, running really fast, but I must do a very poor job of presenting my arguments if my descriptions and performance results come off as "fanboy" prattle...

Keep up the turbo 'boosting', Bill - love reading it - and will get around to following your lead some day... :-)