Do you have a bouncy ride right now?

If you do the yes new struts will help that (a good set of quality struts at least) and eliminate some of the bounce as long as the springs are not overly worn.

As for the curb issue...get used to it is all that can be done. I have been driving lowered vehicles and lowriders for nearly 15 years now and you just have to learn how each vehicle can take what angle of curb. It will always be different in different vehicles and with different setups. Scraping is not going to damage your vehicle at all but it does get annoying and I wouldn't do it at 45 mph either