not the brightst idea not telling insurance company. can get u in alot of sh!t
Seconded!
Just think if you stack your car and injure someone and the insurers send someone out to inspect the damage and notice that you happen to have the wrong engine in there, 2.0 8v to 1.8t aint exactly gonna be hard to miss! The amount of cr@p you would be in would not be worth trying to save a couple of £Â£'s let alone the amount extra you will have to pay next time you want insurance, if anyone will even insure you!
Also police have been known to stop modded cars and check with the insurers that all the mods are declared, if they aint and your insurers void your policy, you get done for no insurance.
If your willing to pay all the money to actually do the conversion it seems daft not to then pay the bit extra to make sure its insured properly especially as the increase from a 2.0 8v gti to a 1.8t gti, in theory, wouldnt even be that much as most specialist insurers rate on the grouping of the donor engine so would hardly even cost anymore.