Hi bakersdelight and welcome to the forum.
While I don't own the 9n or 9n3 version of the polo GTI, I did consider it as a replacement to my mk4 golf. Instead I went new but that's another story.
To try and dispel some the myths you have brought up, as others have said, the 1.8T 20V motor has been in circulation in all manner of VAG vehicles for close to 20 years and as also mentioned, regarded as one of if not THE most bullet proof of VWs motors, especially turbo motors. Parts and labour in reality are no more expensive than any modern day vehicle unless you go to a VW dealership due to how they are trying to position themselves in the market place as a "premium" brand (which us as multiple owners know not to be all that true!) over other vehicle marques.
In regards to running costs, if you are just talking fuel consumption then yes, the colt might be slightly better. Mind you, I don't know much about the colt but the GTI will have service intervals of 15,000kms/1 year. If you're handy on the tools and can carry out the bulk of your own service work (oil, filters, brake pads etc) then you will save a packet. There is also a wealth of knowledge, experience an expertise on this forum because that same motor has been used across a massive breadth of vehicles including Mk4 golf GTI, Audi a3, Audi a4, Audi TT, Vw passat(I believe) etc. The colt while being a Mitsubishi doesn't have that same timeline, is comparitively rare as hens teeth and Inthink you might struggle to find many examples of vehicles than not only share the same basic platform but have clocked up well over 300,000kms.
The choice is yours but I am biased and I know which I would go with
While I don't own the 9n or 9n3 version of the polo GTI, I did consider it as a replacement to my mk4 golf. Instead I went new but that's another story.
To try and dispel some the myths you have brought up, as others have said, the 1.8T 20V motor has been in circulation in all manner of VAG vehicles for close to 20 years and as also mentioned, regarded as one of if not THE most bullet proof of VWs motors, especially turbo motors. Parts and labour in reality are no more expensive than any modern day vehicle unless you go to a VW dealership due to how they are trying to position themselves in the market place as a "premium" brand (which us as multiple owners know not to be all that true!) over other vehicle marques.
In regards to running costs, if you are just talking fuel consumption then yes, the colt might be slightly better. Mind you, I don't know much about the colt but the GTI will have service intervals of 15,000kms/1 year. If you're handy on the tools and can carry out the bulk of your own service work (oil, filters, brake pads etc) then you will save a packet. There is also a wealth of knowledge, experience an expertise on this forum because that same motor has been used across a massive breadth of vehicles including Mk4 golf GTI, Audi a3, Audi a4, Audi TT, Vw passat(I believe) etc. The colt while being a Mitsubishi doesn't have that same timeline, is comparitively rare as hens teeth and Inthink you might struggle to find many examples of vehicles than not only share the same basic platform but have clocked up well over 300,000kms.
The choice is yours but I am biased and I know which I would go with

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