Ok, here's some helpfull info.
31 designates the Stage 3 T31 turbine wheel. This turbine wheel is used in the TA-49, (SC5031, SC3231, SC3431 Sport Compact T3/T4 turbos) TE-32, TE-44,and PT6131.
52 designates the Stage 5 T350 turbine wheel. This wheel is used in the PT52 and PT6152.
69 designates the TO4 69 trim turbine wheel, just slightly smaller than a small shaft P-trim.
76 designates the TO4 76 "P"-trim turbine wheel.
and lastly,
80 designates the GT-Q turbine wheel, which displaced the older Q-trim turbine wheel about 5 years ago.
A = TA series or stock appearing compressor cover as used on stock or TA series turbos.
B = TO4B compressor cover, integrated inlet bell, 3" inlet 2" discharge, .50 A/R, smaller in overall diameter than your TO4E comp cover.
E = TO4E compressor cover, integrated inlet bell, 3" inlet 2" discharge, .60 A/R
S = TO4S compressor cover, integrated inlet bell, 4" inlet 2.5" discharge, .70 A/R.
SP = TO4S compressor cover, integrated inlet bell with either a slotted style
Anti surge ring (Ported Shroud), or the multiple bullet hole style Anti surge ring, .70 A/R. Typically used on Sport Compact or manual transmission equipped applications to help reducer or quell compressor surge and help keep the rotating assembly spooled up between shifts. Here is a link that goes into more detail about Anti surge ports or "Ported Shrouds".
TurboByGarrett.com - Turbo Tech103
Scroll 1/4 the way down the page until you see "Surge line" 3rd line item under Surge line is Ported Shroud.
Here is a picture that shows what a typical Ported Shroud looks like.
H = PTE Race series compressor cover. PT70-PT88 series turbos, featuring 4" inlet, 3" discharge, .75 A/R, Precision logo on discharge of comp cover.
HP = PTE Race series compressor cover, PT70-PT76 series turbos, 4" in, 3" out with Ported Shroud or Anti Surge Ring, .75 A/R, Precision logo on discharge of comp cover.
Stay tuned when next week we'll discuss...... Turbine housings.....
HTH
Patrick