I'm asking a question for a friend who has no internet access, he is putting extractors and a sports system on his HJ 202 red motor and wants to know if retuning the carby is a big issue and will it run well enough to drive it round for a few weeks till he can get it retuned, I cant help him because my new exhaust (3 days old) is replacing a set of old extractors and even though the new system is now 2-1/4" instead of 2" I dont feel much difference, and I have no experience at changing these things over, as any car I`ve owned with extractors has been bought with them already on, any advice I can give him would be greatly appreciated. Thanks.