There is a lot of "stuff" about the 2.7L, some true, some BS.
Without writing an extensive article, I'll pass on some thoughts & experience.
Lets start with the case.
They warp. Spending big bucks for a line bore is not money well spent. It's cheaper to find one that is straight enuff to *line hone*. They collapse across the split and the main bores are no longer round......but undersize perpendicular to the split. A line hone (or drag hone) will get them back to size.....*if the bores are straight.*
The proper insert for studs are "case savers".
The best head studs (IMO) are full thread divilar 993 studs. Henry at Supertech also makes some with the proper expansion rates tho I've never used them. I believe his price is more friendly to boot. This is one place not to scrimp on lesser fasteners. I would never use steel fasteners here.
The machine shop bill (a local outfit) for the drag hone, crank turn, polish, & mag inspect.....case savers.....around 500. Note, do not turn a crank undersize these days. The price of non standard rod & main bearings will stop your heart. A Std/Std crank can be had for around 400.....less than 1/4 the price of them bearings...I shit you not......I have one BTW.
I also have a lovely first under crank...perfect paperweight.
EBS is a good place to have your heads done. Spring for new valve springs
They will check out your valves. Prices are reasonable. I needed all new intake valves ....plus the springs and the bill was around 850 ...tho this was some time back.
New CIS P/Cs are more expensive that RS P/Cs last I looked. The RS cylinders are very difficult to wear out and these sets can often be found in used, in spec condition.
"E" or Solex cams & Webers really wake up the engine and make for an excellent street motor. Gas mileage suffers but you have a lot more fun.
KEEP THE MOTOR COOL. That way the case won't warp. If you can find a non South West motor....one from a cooler climate...there will be less chance of warpage. The late 76 & the 77 motors have the "oil mod" from the factory.
An external oil cooler is money well spent.
Get Bruce Anderson's book & read it twice. "Porsche 911 performance Handbook".
I got a long block for 500. Never pay more than for what you can part out an ughknown motor....unless your mom says it's a good one.