Before I start I have to say you did do a nice looking install. To bad it will not look that way very long. Your method of application is short of what it takes to make one stay on. I already see a place on the front wheel well that is coming up and going to peel.
Here are just a few points and just the tip of the ice burg.
#1. Any vinyl you are going to get for $120.00 for enough to wrap a car is going to be cheap, hard to work with, and not last very long.
#2. Take into consideration if you are going to have to remove it or not someday and the damage it is going to do to your car.
#3. There is a reason shops charge good money to do vehicles. They are trained on the proper materials and know how they will act under different situations. And more important preparation before application like removing all wax and contaminates. Leave wax on a white hood where it gets heat and you will have a giant brown spot baked into your hood when you remove the wrap. They know when to use and not to use adhesive promoters and edge sealers to keep it from coming loose.
Wrap vinyls are made to go on dry with ease without bubbles and wrinkles. They are also made to be removed with ease. Intermediate vinyls are a bitch to remove and you will
cause damage to the paint taking it off. BTW Oracal is one the worst to remove I have found.
Next is Intermediate vinyls are made different then premium wrap vinyls and have way different properties. The biggest is they shrink (really bad) and crack. Any low areas the vinyl was stretched into will lift in about 2 to 4 weeks and will tight as a drum head. When it is time to remove it will come off in little pieces the size of a dime. Good wrap vinyl will come off in one piece without chemicals that cause damage to paint. Just because the manufacture says it has removable adhesive does not mean it removes easy.
So if using $120 worth of vinyl for a DIY on your BMW that is only going to look cool for about 3 months (if that long) before it goes to pieces is worth a $2000 paint job then be my guest. If you want to use cheap vinyl you are mostly likely one of those people that would use Walmart spray paint anyway.
Wrapping cars is not that new and if it was that cheap and easy you would see a whole lot less paint jobs. I am just saying do some research and learning before you screw up a good paint job for a worse looking fake one. If you have any questions feel free to ask. I have been slinging vinyl for almost 30 years and wrapped just about anything you can think of with every kind of vinyl known.