Changing my appearance to get what I want?

You should only make changes for yourself, not for the sake of others. An important question you should ask yourself is will this guys change for you?

Probably not, because people don't change for others, they change for themselves. I assume you want to change for your own purposes as well. If this change does not interest you for your own self image/worth then you really need to stop and ask yourself what it is you're doing.

NOPE. because that makes you a poser

A lot of the skinnier guys are self conscious about themselves being skinny, therefore are really attracted to girls with some meat on their bones. This is just what I've noticed.

If you're making all those changes because it's what you want, it's worth it. But if you're just doing it to impress other people, it's not.
You might have a better chance with those guys, but only if that's who you really are. Guys generally like girls who are comfortable being themselves, so if a guy is interested in you, he'll accept you as you are.

I think that changing things about yourself for the better is a good and healthy thing as long as it is for YOURSELF and not other people. People are going to like or dislike you regardless of what you look like. But if you are doing these things to boost your confidence, I say go for it. But always be true to yourself and never doubt what you have to offer beneath your appearance :)

No. It's not worth it and you realistically won't have a better chance. You may even have worse of a chance because he might not like that you're being true to yourself.