It's pretty cool that the PJ Grady kit uses existing mounting holes and apparently you don't have to drill the SS panels..I'll give you that one. I'll stand by my original comment though that using double sided tape to hold parts on the outside of the car is a bad idea. If the Grady kit uses the front rock screen mounting points for the front flux bands or some other mounting points to keep the parts on securely then that's a different story. Parts have to be bolted on one way or another or it's just not safe.

I'm pretty biased in my opinion though that if you're going to build a BTTF conversion that it should be done accurately. Having extra brackets coming out from places to mount parts isn't true to how the car looked on film. There are just some details that you can't get right without drilling a few holes. If the builder is willing to make those sacrifices then that's their own choice.

My personal opinion/philosophy on converting a car into a time machine is that if you're not going to do it right, then don't do it at all. When people take shortcuts it shows. Attention to detail is what sets apart an accurately done car vs a cringe-worthy mess.