99 Civic EX. It's already got 16" wheels, limo tint and neon under the seats. No neon allowed on outside (not street legal here in CA)

Anyone have any suggestions of decent but not too expensive mods for it?

What do muffler tips really do? Are they worth spending the $$? Will it make the car sound like a fart can?

Do body kits need to be installed by a pro, or can you DIY?

Any help is appreciated.