I was thinking of changing the rear silencer on MY93 WRX for one with a better sound. On calling my insurance company I found out that if it doesn't give a power increase it won't cost extra. Will it be likely to give any increase or should I just tell the ins company it won't?
Also what is the best oil to use?

If you have a Subaru Impreza, And im assuming you have, then a full system would definatly give an increase in power. More so if the downpipe or CATS are removed. If you just place the backbox on then you may get a small increase but id tell them you dont:) the CATS are the biggest performance drag followed by Bore size (eg 2.5-3" etc) followed by any middle section boxes then Id personnally say the back box would be almost the least significant.

the increase youll get from a back box wouldnt warrent telling the insurance company so they can increase your premium as your only talking a couple of BHP if your lucky!!!!;)

As for oil, its down to personal preference. I run GTX Magnatec as fully synthetic can be to thin. However some people may dissagree. Any semi-fully synthetic should be good enough.

Hope this helps:)
Ronnie

Thanks, thats loads of help

Like most people i run a fully synthetic oil (mobil1 motorsport 15w50) it IS better than a semi synthetic as its more resistant to the heat that your engine and turbo produce and wont break down as easily.
I would reccommend you use a fully synthetic oil over a semi synthetic, one of the listed ones is preferable ;)

Mobil 1 Motorsport 15w50
Motul 300v 15w50
Castrol RS 10w60.

Running a semi synthetic oil would be like running unleaded fuel in your WRX, not very healthy for long periods of time, and you have to think that if you only fed your dog on bread and water would it be happy or would you feed it on the best food you could? ;)

Tony:D