ATX tranny upgrades

I'm looking to do some mods on my 99 SL's auto tranny. Please comment and try to answer any questions i have.

Tranny coolers - $50 bucks at autozones or whatever
Shift kits - TL-175 $75
Alto end clutch

1. What model tranny cooler fits in our cars?
2. Are there any other models for shift kits other then TL-175?
There website it pretty beat and there isn't much description on the product. Do you need to remove the tranny to install it? Just the cover, right?
3. Do I need to remove the tranny to install the alto end clutch?
Does it make a difference if i upgrade this or not... the money can be spent else where.
4. I'm not gonna go with the torque converter... sounds to me the increased starting idle is horrible for gas mileage.

Get back to me on your options and thoughts, Thanks

--Respect the GT

any help?