D4X B5753: Corsa Extra SLX 1989 (7-Eleven colours with chrome look beautifully btw.)
D1106: This is a special thing - the first version of Mx Leader, produced briefly (a few months at the beginning of 1992!), definitely for a connoisseur. The only difference from the last version of Corsa Extra Max was the top tube and the top lugs (just in case: BB cover is Max or "EM" logo?). By the way, a new time record was broken between building the frame and selling it.... to this day it was only 1.5 years
H D2665: Don't worry about the SPX sticker - it was used until 1988 and the frame is from 1992.... We have a choice: SL/SP, SLX/SPX, TSX, 653, 753, 531, gara/cromor (Max and Mxl certainly don't fit). There are some markings under the BB cover paint (but not readable without removing the paint). Non-invasive method: remove the front wheel and check the inside of the steering tube - if you see 5 "riflings". (arranged like a barrel) it leaves you with the first 3 options - a good Columbus. Then you twist BB (from the more convenient side) and check if the tubes entering the BB cover also have "riflings": if so - we have SLX/SPX or TSX, if not - we have SL/SP (in each case with the advantage of "heavy" tubes, that is SPX or SP within the size above 56). The only difference between SLX and TSX (verifiable) is the length of "riflings" in the bottom tube of the frame: SLX short at the ends of the tubes, TSX long over the entire length of the tube. Any effective method will be good (except for sawing... with microcamera or imprinting in Play-Doh inclusive...
If the inside of the steering tube is smooth, Reynolds remains: 753 is out due to chrome, 531 has probably not been used anymore - 653 remains... Also not bad