Stay at 84mm or if you have to bore, no more than 84.5mm. Some people have good luck with B20's, some dont...
I wouldnt rev a stock b20 bottom end past 8k personally. If you want to rev higher and build your engine to be more rev friendly, look at the +.137" length rods with some nice pistons.You could even de-stroke it with a gsr/itr crank for even higher rpm longevity, but youll lose displacement. If your going all motor, you probably dont want to do this.
I think Wiseco pistons are nice myself but CP's are said to be good too. I saw some sharp edges/poor machining on SRP's before so I dont care for them. Ross is also supposed to make a good piston.Ive never used them though.
If your staying all motor, theres some pretty new high compression cast pistons out that is supposed to be pretty hot.
At the very least, have a machine shop install ARP rod bolts since theyre the most stressed bolt in the entire engine. New oil pump too.

2 Liter all motor goodness- YUMMY