Quick Question: Laser/Telstar gearboxes

[JeremyK]

Okay so recently I have been having alot of trouble with my Three-Speed Auto in my Telstar, I think it needs to be overhauled, which requires removing the transmission, and that got me thinking!

If I am going to remove the transmission, why don't I just replace it with a better one?

So these are my options:

1. Change to another 3-speed auto exactly the same as this one or get this one refurb'd, whatever is cheaper
-Advantages: Relatively easy to remove and refit the tranny when everything connects up the same
-Disadvantages: It has the worst gear ratios in history and screams on the highway, has no power as its like starting off in second gear (that being said it does quite well!) and uses much more petrol.

2. Change to the ECAT 4-speed auto used on the 2.2L injected motor
-Advantages: Quiter on the highway, engine does alot less revs. More modern transmission and hopefully wont suck 98% of the engines power.
-Disadvantages: The first three gears are as bad as mine in the three-speed. Could be hard to get it working as it is Electronic connecting to a non-electronic motor (I have the carb motor, I think the tranny is controlled by a seperate computer anyway BUT surely it takes some input from the motor? Input that it wouldnt be getting from my motor?)

3. I have a spare KH Laser with a spare 5-speed gearbox in it that works fine, considering the three speeds are the same in the Laser and Telstar, I assume they bolt up the same or at least can be adapted? And that this would also apply to a manual? If this is the case, then option three is to change it to the Lasers 5-speed manual.
-Advantages: Much better ratios resulting in better performance and fuel economy. Also revs less on highway. Also means if this motor ever dies and needs to replaced, I have the option of changing it to the Turbo or the 2.2L Injection or even the diesel without changing the tranny.
-Disadvantages: Time consuming to change it to a manual. Will lose the self shifting which is kind of nice if you cant be assed changing gears.

IF I had unlimited money and time I would probably go for the ECAT 4-speed BUT, I am unsure as to whether I can get it to work with this motor, and if it will eventually die as well, maybe its better to stick with the simple and reliable manual?

Thoughts and help is appreciated!!