Rebuilding an existing car, do I need a new IVA test?

[snapper]

Re building an existing car is not a problem, radicaly modifying could be an issue and require another IVA test.
Personally i would enhance the existing car, if you understand what i mean
Enhancements and safety modifications do not require an IVA test, changing the engine to a different size and therefore tax bracket is a DVLA thing not IVA