Congrats on the show wins....
Been there done that on the manifolds. Have them machined and put them back as they did at the factory - no gaskets. I ordered a set of new bolts, washers and locks. Not sure what brand etc - was just supposed to be better than new.
Browse this thread on the manifolds.
If I remember correctly a 50/50 anti-freze mix will not boil until 250 deg with a 13lb cap. I'm sure the experts will check me on that (I hope anyway).
My temp gauge is normally just above the E in normal driving then rises to just above the M at about 75 mph on the interstate. Will park just above the M in hot stop and go traffic but hasn't boiled over since I installed the new radiator.
I'm sure the shroud will make a difference - I don't have one.
On the speedo - might just need to be cleaned and a drop of oil (specific oil for instruments not just the regular stuff) but no guess other than tire size on the calibration.
Mine is off too but I'm running 225/75/14's.
I hit a short entrance ramp the other day with a guy right on my tail - semi on the left that couldn't move over and running out of entrance ramp fast. Nailed it rather than have the guy slam into my rear end. I was going by folks pretty fast and thought.....man these peeps around here drive slow..... then I looked at the speedo......about the same as you 105 ish.
Oh...... so that's why I was passing everyone.......
Good luck - keep us posted.