Avoid those Chinese trackers if you can .They are inefficient and they have high failure rate .Just invest in a reputable brand and you will never regret.I am an installer and the first batch i did some Chinese trackers but the all failed and my clients got furious.We decided to exclusively deal with Teltonika and I have never had issues,furthermore even the most basic tracker has functions that even the high end Chinese brands don't have e.g fuel monitoring and the speed governing function without need for additional accessories.I have installed some in excavators and wheel loaders for monitoring work hours ,the list is endless so many ways to use the device. The initial cost is higher compared to the Chinese brands that we have in the market.Infact NTSA have listed one of the Teltonika Tracker model as authorised speed governor.
The tracking system is flexible allowing the user to generate detailed reports.
A certain bus company operating on MSA - NRB route has changed to this brand after experiencing problem with the Chinese ones.I am not trying to make a sale just passing information that will help you in your decision making.

It costs 15000 (device + installation within Nairobi) An annual fee of 1400 from the second year after installation.

1. Model matters. If changing from TRH to 1KZ, then you'll have to switch both engine and gearbox. If from TRH to 2KD, engine only. In all cases, ECU lazima ubadilishe pia.

2. Some 'leg work' is called for. Dar-es-Salaam road and Baricho road neighborhoods for the parts.

3. I've heard of some who've done it but I don't know them personally. Efficiency depends on age of engine/ condition it was in when you bought it and driving style, among other factors.

Given the dearth of professionals with sufficient skills to successfully pull off such a conversion, I would aver so. However many factors also come into play, chiefly the distance and terrain. If not too hilly and about 100km one way, I'd think petrol is alright.