1. I think stainless exhaust systems start at around £300 as they usually come as a cat back full system. you may see some slight power gains and it will sound different for that though, some people don't like the sound of exhausts, others do.
2. for a second on startup is perfectly normal, it uses oil from engine to feed and lubricate it, so for a second on startup until oil pressure gets that far is fine, sounds like your veriator is in very good condition.
3. don't ask a mechanic to do body work, they're mechanics not body shop. take it to a proper body shop. you can go all out for an expensive professional place but for an older car and small damage area you could go for a cheaper back street sort of job that probs won't cost more than couple of hundred.
4. you need some proper leather dye and feed cream. I think gliptone do some pretty magical leather stuff.
1999 156 1.8TS Sport Pack 3
2001 166 3.0 V6 24V Super
2003 156 GTA 3.2 V6 24V
2005 156 1.9 JTDM-Jet Sport
2008 159 1.9 JTDM Lusso
1997 GTV 2.0TS Lusso
2001 147 1.6TS Lusso