I'm about to pull the trigger on an Olympus D-OM5, any recommendations?

I think I'll be buying the OM5 ( simple description ) plus the following lenses:

1. 12-50mm

2. 7-14mm

3. 20mm f/1.7

4. 40-150mm

I'm now using a Nikon D700 + various lenses. Good camera but too heavy for my vacation trips. Time to get back into Olympus. I still have My OM4Ti from the last century and I loved it. Also have some lenses from the OM4Ti, can I use them with some kind of adapter. Do I have to view and shoot stopped down??

Thanks for any help in advance.

I asked this same question on the the two other sites and someone mentioned that I should ask it on this site. They were nice enough to answer most of my questions.

One more question, I would like to get back into street photography ( check my site if you care to see what I mean ) and have been waiting patiently for a digital camera to replace my trusty Leica M3 and Mr. If I pre-focus the OM5 say at 12 ft., will the shutter go off with almost no lag or am I stuck with the same 1/2 sec. lag I was getting on my Canon S95?? That turned out to be unacceptable!