Hey guys I have got a 1997 29 fever with twin 454 mags and was thinking about putting on the emi manifolds with the stock looking risers . The question is is it worth it ?

It all depends on what you are trying to accomplish. If you are just looking to replace your stock manifolds because they are rusting out, then perhaps. I am not sure what stock replacments cost. If you are doing it for greater performance but don't plan to do more, then I don't think it is worth it as you would be lucky to see anything on the speedometer unless you are planning to do more performance improvements like a cam heads etc. If you are doing more performance improvements then they will definately make more, but then I would think you wouild want the stainless risers with them rather than the stock appearing ones. I have had EMI's and was very happy with them. If you are not doing anything other than the exhaust, you won't see much of a difference.

The problem is I dont want to lose the silent choice .

i sold a set( NEW) to a friend of mine last year and he got no performance gains,he said it was alot louder tho..if your looking for somthing cheep i would look into lightening headers,i put a standard steel set with ss inners on one of my customers boats over 10 yrs ago and they still look as good as the day i put them on inside and out..dont let lightening headers fool you THEIR A GREAT HEADER and jen makes headers for other popular mfr out their..

Whats the cost differance between the two ?

What are your long term goals? Like the others have said you will not see a big top speed gain with this upgrade alone. You may see 1 or 2 mph max. If you plan on upgrading your cam then get the manifolds with the long risers are needed for reversion. The silent choice along with the y-pipe will need to be removed. If it is too loud add baffels to your tips.