I recently came across a shop selling a bundle of different size silicon pipe to replace the hoses in the engine bay. Ive never done this before so was wondering if there are any drawbacks?

They have a nice blue colour that i think will look cool, but are these silicone products reliable, i.e good with the heat?

This depends on silicon quality.
Silicon is only good for use with air (vacuum) or coolant. Would use only brand name for coolant pipes thought.

Ok i didnt really make note of the brand. Think i'll give them a try for the vacuum ones.