ThinkPad T400 upgrades option

[DLinks1292]

Hi, Im new member of this forum, first of all, I'm really sorry for my bad english. I'm currently own a T400 with Intel iGPU variant and already using whitelist removed bios, and I see some room that I can Improve for my T400, the obvious one will be changing the CPU, bumps up the ram, etc, but I'm still have some question for my specific models:

1) CPU upgrade,, In my country, is hard to find good CPU like the T9600 or Apple specific E8335 CPU with a good price, except I sourced it out from AliExpress, which is cheap, but I still have to pay ridiculous amount Import duty and VAT. I saw several CPU like T9400, T9500, and few T9550 with a good price, but is that worth to upgrade from my stock P8400? Especially considering the 35W TDP they have.

2) About the MiniPCIe Slot, there's unused WWAN and Turbo Memory Slot in my device, I already tried populating both with my spare WLAN card, all of it confirmed detected in device manager, but the card I put on WWAN card show it hardware disabled, does it meant WWAN slot is wired to USB only? if yes, any suggestion what card to populate on that slot? in case of the turbo memory slot, I've read that using ThinkMods ExpressCard to NVMe SSD is worked on T400, and I confirm using GDC EXP Beast via ExpressCard and connect it via PCIe to NVME card it worked normally but without boot capability (There's a workaround using clover to boot it but I not tried yet), now, instead using those janky setup, can I use the Turbo Memory slot instead of ExpressCard slot? I'm Planning to buy Mini PCIe to M.2 Riser to connect it, will it works? I know the speed will be capped around 250MBps since it use PCIe 1.1 speed, but it nice to have secondary storage without sacrificing the Ultrabay drive.

3) Display upgrade, There's any better panel replacement for my stock CCFL 800p display? at least it will nice if use bright LED panel instead CCFL ones, well I can change the panel to use LED strips but as you may know, like other laptops, T400 using proprietary CCFL Driver, so that mod will not possible. Or maybe the panel is not bright enough because the CCFL is degraded? I can see it in office/home environment, but not in indirect sunlight or well lighted coffee shop.

4) Bluetooth Module, any recommendation which type of ThinkPad bluetooth module I use? since mine doesn't equipped with the module.

Sorry for the long question, any help and suggestion will be appreciated!

[RealBlackStuff]

Get the T400 manual from the HMM link at the top of this page.
Lots of T400 info here: https://mcdojf.wixsite.com/t400

Screen options (all 1440x900, LED):
AU Optronics B141PW04 V.0-Anti Glare
AU Optronics B141PW04 V.0 HW2A
AU Optronics B141PW04 V.0-Glare
AU Optronics B141PW04 V.1
AU Optronics B141PW04 V.1 HW0A
LG Philips LP141WP3 (TL)(A1)
Samsung LTN141BT09-001
If you go from CCFL to LED, you also need a new LCD cable and LED-board, see the Parts list in the HMM.

[DLinks1292]

Get the T400 manual from the HMM link at the top of this page.
Lots of T400 info here: https://mcdojf.wixsite.com/t400

Screen options (all 1440x900, LED):
AU Optronics B141PW04 V.0-Anti Glare
AU Optronics B141PW04 V.0 HW2A
AU Optronics B141PW04 V.0-Glare
AU Optronics B141PW04 V.1
AU Optronics B141PW04 V.1 HW0A
LG Philips LP141WP3 (TL)(A1)
Samsung LTN141BT09-001
If you go from CCFL to LED, you also need a new LCD cable and LED-board, see the Parts list in the HMM.

thats the neat part for LED one, seller in my country doesn't include the LED control board, maybe im trying the samsung or LG one, or maybe I just need to change the CCFL lamp on my old LCD? anyway thx so much for the answer!