Chordless impact wrenches

[pdedse]

I'm in the middle of a suspension project for my DR650--putting on a new rear shock.  I got the shock out and decided it was a good time to check the swing arm pivot bolt and bearings, other linkage as sometimes from the factory they don't have much grease.  Indeed, I was able to pack in quite a bit more on the swing arm pivot bearings.  I moved on to the dog-bone links and one bolt I loosened fine to detach swing arm from the bike, but the other end of the dog-bones has another bolt with bearings.  And I cannot get this bolt free with what I have on hand.

I've tried PB Blaster, applying heat, I'm using a 1.5' breaker bar, acetone and so far the bolt won't budge.  I couldn't find a metal cheater bar I've used in the past, but that might be my next step.  I did find my old air impact wrench, but...it's over 30 years old and doesn't work any more and my even older compressor might not be working well with the higher psi settings.

I started looking at air impact wrenches and, wow, the options. In the back of my mind I thought I might buy a new air impact and I don't even know if my compressor will work with it.  Then somebody on another forum asked me why don't I just buy a chordless impact wrench.  

That didn't even register with me.  Chordless...whaaa...?  My first thought was how does the wrench get air from the compressor if there's no chord?    I'm not always quick with mechanical related things.  After a few online searches it dawns on me that chordless means they got batt...ooooohhhhhh. 

  

Cool! And I resumed my search.

How many chordless impact wrench brands does this planet need?  And how much impact wrench power do I really need considering I'm working mainly on motorcycles?

So with about 20 different internet pages open and my head spinning, I see that perhaps my first decision is whether to go with 3/8" or 1/2".  Seems that some people say 3/8" will do 90% of what you want, others say just go with 1/2" but be careful.  The 3/8" impacts seem to be smaller and lighter...and cheaper, but maybe the reason I need an impact wrench is for that 10% of the time.

Questions: 
1) If I'm thinking for this current 19mm stuck bolt, 3/8" OK or go for the bigger 1/2" because if I have it, I'll use it for more "stuck things" in the future?

2) Brands: Since I haven't even used my air impact wrench in probably 20+ years, I ask myself a) how often will I use it? and b) how long will I live?  In other words, maybe I don't need the best of the best.  I'd like to stay around $200 or less with battery included, which allows me for lots of brand I've never heard of, and maybe allows me to buy a lower end "nice one".  Many seem to like Milwaukee.

--a 3/8" Milwaukee mid-torq impact (3.4lbs / $200 w/out battery)
--a 3/8" Milwaukee M18 compact (2.7lbs / $150 w/out battery)
--a 1/2" Milwaukee M18, heavier
--or one of the cheap brands: aeropro, Seesii, Protmex, Agsen, Sundpel, etc.

--other recognized by me brands: dewalt, ingersoll rand, ryobi, makita, craftsman

--one that you recommend because of your own experience?

Thanks for any input.  If the cheater bar works, I may not even bother, but at the same time maybe an impact would help me as I age and loose some strength.