[Boma]

What kind of modifications would it require? I can't afford to buy the Turbo Back all at once.

 

[Nessal]

Actually, there are some catbacks and DP that would not go together unless you have an adaptor. There are also ones that will fit like a glove. If you are worried about fitment issues, I would save up till I have enough for a turbo back. That way you know that the whole kit would bolt right up.