My '04 Impreza 2.5TS has 105,000 miles on it without ever having any major repairs and I'm going to bring it in to the shop for them to do the timing belt, water pump, head gaskets and spark plugs. Is there any other maintenance I should ask them to do while they have the engine out? Are there any (reasonably priced, aka under $250) mods I could ask them to install to get a little boost in performance? I looked at performance timing belts but form what I read, if I'm not modding the crap out of my engine (which I don't plan on doing) then there's no reason to get one of those. Is this correct?
I'm comfortable doing basic maintenance/mod stuff myself but I don't feel comfortable mucking around with the engine, that's why I am bringing it in.