plug n play td chip any good ?

hi
are plug n play td chip any good ?
state to improve mpg and performance

Landrover Freelander TD4 2.0 2.2 TDV6 2.7 3.0 Diesel Tuning Performance Chip | eBay

Wouldn't be my first choice.

A proper map is the best way to go. Generally plug in boxes just increase the injector pulse. Ie. add more fuel.

They work but they are crude.... In my opinion

£75 vs £150+ genetic remap - if custom remap then £250+
got 100% with great feedback for the plug n play chips on ebay with buyers saying up to 10mpg improvement

ie add fuel would it not make mpg consumption worse

i remember the resistor trick on petrol fuel injector cars which did make mpg worse so i know where your coming from

synergy 2

Tuning-diesels for low cost diesel tuning.