At best a decent exhaust will offer 4-5 bhp extra, it's likely to be a lot loss for a mid-range silencer 3 tops most likely 1-2bhp, so personally I'd say just go for it with respect to the power, no one is going to question it. As to fitting it, it's just take off the old one, maybe 3 bolts, make sure the ends of pipes are clean, add a little exhaust sealant, put together again (same 3 bolts you took off) and wipe excess paste off. Shouldn't take more than 20-30mins Though will then have to wait for the past to dry, this can be done by leaving the bike to idle, until exhaust gets to operating temperature + 5-10mins extra. Don't rev it during this time. ♦Put a new can on mine not long ago, was really easy.