I'm looking into getting lowering springs for my 2005 infiniti g35 coupe. Which brand would be best? Should I install them myself or take it somewhere to do it? how much would it be if i took it somewhere else? thanks guys!

 

https://g35driver.com/forums/brakes-...w-updates.html

By asking if you should take it somewhere shows that you are not confident/competent in your abilities to do your own work...therefore yes, you would probably want someone else doing it.
Do some research before making your purchase.

 

I would agree with the above, I have been wrenching on my cars for 44 years, so it didn't bother me a bit to tear into the suspension. I replaced shocks and springs in short order. Now when it came to the bushings, I let someone with the proper tools do it and I'm glad I did. The spring install is not that hard, but you need to have a floor jack, jack stands, and a good socket set, air wrenches would be even better (I didn't have them but got it done.) to break some of the nuts that might be rusted up after a long time. There are several DYIs on this here and over a My350z.com

Good luck with your decision.