  We present precision calculations of the processes e+ e- -> 4-fermions in
which the double resonant W+ W- and ZZ intermediate states occur. Referring to
these latter intermediate states as the 'signal processes', we show that, by
using the YFS Monte Carlo event generators YFSWW3-1.14 and KoralW-1.42 in an
appropriate combination, we achieve a physical precision on the WW signal
process, as isolated with LEP2 MC Workshop cuts, below 0.5 per cent. We stress
the full gauge invariance of our calculations and we compare our results with
those of other authors where appropriate. In particular, sample Monte Carlo
data are explicitly illustrated and compared with the results of the program
RacoonWW of Denner et al. In this way, we cross check that the total (physical
oplus technical) precision tag for the WW signal process cross section is 0.4
per cent for 200 GeV, for example. Results are also given for 500 GeV with an
eye toward the LC. For the analogous ZZ case, we cross check that our YFSZZ
calculation yields a total precision tag of 2 per cent, when it is compared to
the results of ZZTO and GENTLE of Passarino and Bardin et al., respectively.
