Arm what?

I'll defer for the experts for most of your questions, but I do know that solid bushings can make for a tough ride. Do you drive your car to work everyday, in traffic? If so you may want to consider comfort as a factor as well as performance.

It's no use having a bat-outta-hell car as your daily driver if you find yourself wishing you had a Civic so you can ride to work without feeling like you've just been through Navy Seal training

... I learned this the hard way with one of my earlier Mustangs. In that case, I had 3.73s installed, which sure woke the car up but I spent a lot of time on the highway and I really got annoyed when it felt like I was in third gear at 75mph for hundreds of miles.

Most people will tell you that they reduced the wheelhop with the LCA's but the catual culprit is the Hydra Bushing in the UCA.

Go with poly bushings on both ends. I eliminated all of my wheelhop with a Steeda Adjustable UCA . I then installed the Steeda LCA's.

Some people use fixed UCA's but sometimes get into pinion angle issues once the car is lowered.

There are many good brands out there. BMR,CHE,Metco,Steeda.

DO NOT USE A GREASE GUN TO LUBRICATE THE BUSHINGS EVEN IF ZERKS ARE PROVIDED.

Get a 8OZ tub of Energy Suspension Formula 5 Prelube from Jegs or Summit. Disassemble the bushings and lube by hand (insert joke here). Do this once a year and you'll never hear a poly bushing squeak.
Keep a can of brake cleaner on hand cause this grease sticks like glue.