Big big important note, all information is taken from http://rrpg.jp/mary_skelter_2/. Seriously, they have a good site, and they have full guides for a lot of stuff, check them out.
I have now beaten the game, so all names should now be correct. The only one that could be wrong is the Power Ribbon, because in my playthrough I never found a headgear with those stats so I couldn't confirm the name.

There is only a single weapon that has any positive change from TP, and even then it's debatable. Oh how I miss you so, MS1og Goblin Hammer.

White Whip: ATK+35, AGI+43, LUC+30
SM White Whip: HP+500, ATK+21, AGI+26, LUC+18
Changes: HP+500, ATK-14, AGI-17, LUC-12

Headgear fares a bit better, having things that actually improve.

Melee Headband: ATK+1, DEF+4, MEN+1
SM Melee Headband: ATK+1, DEF+4, MEN+4
Changes: MEN+3

Power Ribbon: ATK+3, DEF+2, MEN+8, AGI+3
SM Power Ribbon: ATK+4, DEF+8, MEN+7, AGI+4
Changes: ATK+1, DEF+6, MEN-1, AGI+1

Aegis Helm: DEF+37, MEN+7
SM Aegis Helm: DEF+60
Changes: DEF+23, MEN-7

Ruby Earrings: DEF+42, MEN+6, AGI+6
SM Ruby Earrings: DEF+68, MEN+21, AGI+8
Changes: DEF+26, MEN+15, AGI+2

Foe Headband: DEF+8, MEN+43
SM Foe Headband: HP+10, DEF+39, MEN+13
Changes: HP+10, DEF+31, MEN-30

Curly Wig: DEF+45, MEN+7
SM Curly Wig: DEF+69, MEN+54
Changes: DEF+24, MEN+47

Vatic Earrings: DEF+50, MEN+11, AGI+15
SM Vatic Earrings: DEF+41, MEN+70, AGI+19
Changes: DEF-9, MEN+59, AGI+4

Prodigy Tiara: HP+20, SP+20, ATK+8, DEF+11, TEC+15, MEN+60, AGI+15
SM Prodigy Tiara: HP+25, SP+25, ATK+10, DEF+109, TEC+25, MEN+81, AGI+12
Changes: HP+5, SP+5, ATK+2, DEF+87, TEC+10, MEN+21, AGI-3

Armor also has some decent changes, we stay on a good track.

Prisoner Uniform: DEF+1
SM Prisoner Uniform: HP+25, DEF+14, MEN+5, LUC+1
Changes: HP+25, DEF+13, MEN+5, LUC+1

Cloth Armor: DEF+2, MEN+9
SM Cloth Armor: DEF+6, MEN+8
Changes: DEF+4, MEN-1

Ghillie Suit: DEF+14, MEN+2
SM Ghillie Suit: DEF+16, MEN+18
Changes: DEF+2, MEN+16

Oak Armor: DEF+21, MEN+2, AGI-15
SM Oak Armor: DEF+19, MEN+21, AGI+9
Changes: DEF-2, MEN+19, AGI+24

Nurse Uniform: DEF+26, MEN+3
SM Nurse Uniform: DEF+58, MEN+60
Changes: DEF+32, MEN+57

High & Low: ATK+4, DEF+4, TEC+10, MEN+29, AGI+15
SM High & Low: ATK+4, DEF+40, TEC+13, MEN+43, AGI+9
Changes: DEF+37, TEC+3, MEN+14, AGI-6

Scientist Coat: SP+15, DEF+25, TEC+20, MEN+4
SM Scientist Coat: SP+19, DEF+83, TEC+44, MEN+85
Changes: SP+4, DEF+58, TEC+24, MEN+81

Pilot Suit: DEF+8, MEN+38
SM Pilot Suit: DEF+56, MEN+60
Changes: DEF+48, MEN+22

Recoil Jacket: DEF+8, MEN+42
SM Recoil Jacket: DEF+59, MEN+63
Changes: DEF+51, MEN+21

Lucky Dress: DEF+48, MEN+10, LUC+20
SM Lucky Dress: HP+25, MEN+60, LUC+60
Changes: HP+25, DEF-48, MEN+50, LUC+40

Bracelets keep the train going with some good changes, and theres no good SM consumables, so this is our last section as well. We miss you, SM Jelly Supplement.

Prisoner's Shackles: DEF+2
SM Prisoner's Shackles: HP+10
Changes: HP+10, DEF-2

Cursed Ring: TEC+5
SM Cursed Ring: HP+10, DEF+12
Changes: HP+10, DEF+12, TEC-5

Smart Watch: TEC+6, MEN+14
SM Smart Watch: TEC+15, MEN+15
Changes: TEC+9, MEN+1

Life Armband: HP+100, LUC+4
SM Life Armband: HP+188
Changes: HP+88, LUC-4

Thank you for reading this guide, check out rrpg, and have a nice day :)