Thanks for welcomes and advice. Lots to think about.
I appreciate that an early S1 makes the best base car (weight is everything) but the car has to double up as a second road car and be acceptable to the missus - I'm therefore not looking to be Class A8 champ (I'd splash on a two-eleven if I wanted that

). I'm really looking for a road car that I can do occasional sprints/climbs in. This season is proving too much for me (I'm scheduled to do 23 competive events as far afield as MIRA, Olivers Mount, Anglesey, Harewood blah blah) and I'll be doing much fewer events next year. I'll be driving to/from all events - no trailers for me (not yet anyway)!
If I sold the MX-5 (and my massive collection of bits) later, I could afford some engine tweeking too. Ever since I drove Anglesey in a mate's 260bhp MX-5, I quite like superchargers
I'm in no desperate rush. I'll be competing the MX-5 for the rest of the season (only 11 events to go!).
My racing blog:
www.racingfive.co.uk
2001 VX220 NA - SOLD
2002 Seat Alhambra - family towcar shed
1996 Volvo 940 Sports Edition - winter shed
1983 Mercedes 280SE - dictator shed
2001 Citroen Saxo VTS - hillclimb shed