4.2 versus 4.5 tuning

[wantacerb]

am looking into purchasing a cerb 4.2 or 4.5.is the 4.2 able to be tuned the same as the red rose conversion for the 4.5.realise the 4.2 is allready fast but the 4.5 red rose is stunning but i have my eye on a 99 4.2.what are the pitfalls with the 4.2 and what should i look out for 99 with 25000mls